,,! ,,elem5ts ,,( ,,qualitative ,,*emical ,,analysis ,,) ,,special ,,consid]ation ,,( ,,! ,,application ,,( ,,! ,,laws ,,( ,,equilibrium ,,& ,,( ,,! ,,mod]n ,,!ories ,,( ,,solution ,,by ,,julius ,,/ieglitz ,pr(essor ( ,*emi/ry 9 ! ,univ]sity ( ,*icago ,,volume ,i ,,p>ts ,i ,,& ,,ii ,,fundam5tal ,,pr9ciples ,,& ,,_! ,,application ,illu/ration ,,new ,,york ,,! ,,c5tury ,,co4 #aibj ,,copyright1 #aiaa1 ,,by ,,! ,,c5tury ,,co4 ,pr9t$1 ,octob]1 #aiaa ,repr9t$1 ,augu/1 #aiab ,repr9t$1 ,octob]1 #aiac ,repr9t$1 ,octob]1 #aiae ,repr9t$1 ,augu/1 #aiag ,repr9t$1 ,janu>y1 #aiai ,repr9t$1 ,augu/1 #aiai ,repr9t$1 ,novemb]1 #aiai ,repr9t$1 ,july1 #aibj ,,preface ,9 v5tur+ to add ano!r book on ,qualitative ,*emical ,analysis to ! long li/ ( publications on ?is subject1 ! au?or has be5 mov$ *iefly by ! (t5 express$ wi% ( /ud5ts & fri5ds to h 8 lectures on qualitative analysis r5d]$ available = ref]5ce & = a wid] circle ( in/ruction4 ,p>ts ,i & ,,ii ( ! pres5t book embody ^! lectures 9 ! =m to :i* !y h develop$ 9 ! c\rse ( ! la/ sixte5 ye>s1 s9ce1 9 #ahid1 ! tea*+ ( analytical *emi/ry1 along ! l9es foll[$1 0 fir/ sugge/$ by ,o/wald's pione] ,wiss5s*aftli*e ,grundlag5 d] ,analytis*5 ,*emie4 ,! au?or believes t in/ruction 9 qualitative analysis1 besides tea*+ analysis prop]1 %\ld dem& ( ! /ud5t a v di/9ct advance 9 ! /udy ( g5]al *emi/ry1 & %\ld also1 consci\sly1 pave ! way = "w 9 quantitative analysis1 if x is n1 inde$1 accompani$ by "w 9 t subject4 ,! pr(essional me?od ( "w1 :e!r r\t9e or rese>* "w ( ! academic or ! indu/rial laboratory is involv$1 inevitably consi/s 9 fir/ mak+ an exhau/ive /udy ( ! g5]al *emical aspects ( ! subject "u exam9ation3 x includes a ?or\gh /udy ( books ( ref]5ce & ( ! orig9al lit]ature on ! subject2 & :5 ! exp]im5tal "w is f9ally und]tak51 x is c>ri$ out ) a critical1 se>*+ m9d1 :i* que/ions e obs]vation made1 e process us$4 ,! me?od ( in/ruction 9 ?is book aims at develop+ ^! habits ( ! pr(essional1 productive *emi/4 ,= ! reasons giv51 a r ?or\gh & some:at critical /udy is fir/ made 79 ,"p ,i7 ( ! fundam5tal g5]al *emical pr9ciples :i* are mo/ widely involv$ 9 analytical "w4 ,! applications ( ^! pr9ciples to ! subject matt] ( elem5t>y qualitative analysis are !n discuss$ 79 ,"p ,,ii71 9 close/ connection ) ! laboratory "w cov]+ ! /udy ( analytical reactions 79 ,"p ,,iii74 ,! mat]ial is pres5t$1 n z a f9i%$ subject1 b z a gr[+ "o1 ) :i* ! pres5t g5]ation ( *emi/s is /ill busy1 & :i* conta9s _m important1 unsolv$ problems ( a fundam5tal "*4 ,num]\s ref]5ces to /&>d works & to ! curr5t lit]ature are giv51 ( :i* ^? suitable = read+ by ! "y /ud5t are specially designat$4 ,! obvi\s dem& is !reby made on ! /ud5t to aim to rema9 9 t\* ) ! gr[? ( ! sci5ce1 aft] he has complet$ 8 /udies "u ! guidance ( an in/ructor4 ,f9ally1 to ar\se & develop ! critical1 que/ion+ attitude ( ! pr(essional *emi/1 ref]r$ to above1 ! subject matt] ( ! laboratory "w1 giv5 9 ,"p ,,iii1 is put v l>gely 9 ! =m ( que/ions1 :i* dem& n only c>eful obs]vation on ! "p ( ! /ud5t1 b also a ?\ghtful int]pretation ( ! obs]vations made4 ,9 ! exp]i5ce ( ! au?or1 al?\gh ! majority ( /ud5ts att5d+ 8 lectures _h already acquir$ "s k ( *emical & physical equilibrium1 ( ! !ories ( solutions & ( ionization & ( _! applications1 ! m exhau/ive treatm5t ( p>ts ( ^! subjects & ( relat$ topics1 to :i* a c\rse 9 qualitative analysis l5ds itself1 has be5 ( p>ticul> b5efit to !m1 br++ !m into clos] t\* ) ! me?od ( detail$ /udy ( a *emical topic1 ?an ! broad]1 m v>i$ "w ( g5]al *emi/ry c\rses usually does4 ,?r\gh\t ! !oretical treatm5t ( ! subject1 ! attempt is made to prep>e ! /ud5t = a m g5]al quantitative expression ( *emical relations4 ,= ?is reason1 *emical & physical equilibrium con/ants are giv5 & us$1 :]ev] x is possible4 ,! au?or is aw>e t ^! con/ants h1 9 "p1 only a tempor>y /&+2 t m exact "w w cont9ually modify _! num]ical values &1 probably1 limit ! field = _! rigor\s application4 ,! latt] facts c be impress$ on ! /ud5t & /ill ! invaluable pr9ciple be inculcat$ 9 8 m9d1 t *emi/ry is /riv+ to express its relations1 z f> z possible1 9 ma!matical t]ms1 exactly z its si/] sci5ce1 physics1 has long be5 do+4 ,at ! same "t ! treatm5t ( physico*emical topics has be5 kept )9 ! b\nds set by ! subject matt]1 & by ! *emical maturity ( ! /ud5ts address$3 x is elem5t>y 9 =m1 & quantitative relations are us$1 9 ! ma91 only to elucidate qualitative facts4 ,! rigor\s developm5t ( ! subjects pres5t$ & _! elaboration f a purely physico*emical /&po9t are left to advanc$ c\rses4 ,x has be5 f\nd t ?is me?od int]e/s ! bett] class ( /ud5ts 9 seek+ su* advanc$ c\rses4 ,! relations ( qualitative to quantitative analysis are t\*$ ^u 9 ! !oretical treatm5t1 :]e x has be5 feasible to d s4 ,! laboratory me?ods aim also at beg9n+ ! tra9+ ( /ud5ts 9 ! habit ( accuracy dem&$ by quantitative analysis1 by lay+ special emphasis on ! me?ods ( detect+ traces ( a numb] ( ! common elem5ts & by requir+ a report on ! relative quantities ( compon5ts f\nd4 ,! /udy ( reactions is c>ri$ out1 almo/ :olly1 ) solutions ( kn[n & uni=m mol> conc5tration4 ,h[ev]1 ! actual developm5t ( quantitative accuracy is left to ! in/ruction 9 ! c\rses 9 quantitative analysis1 9 :i* a successful tra9+ 9 ?is direction is f> m readily atta9$4 ,simultane\s c\rses 9 ! two bran*es ( analysis seem to ! au?or to be highly desirable1 :5ev] practicable4 ,! /udy ( quantitative analysis adds neatness ( manipulation & accuracy to ! "w 9 qualitative analysis2 & ! latt] supplies ! opportunity = ! fur!r developm5t ( a /ud5t's k ( g5]al *emi/ry1 = :i* !re is a mu* small] scope 9 quantitative analysis c\rses1 & ?us relieves a condition :]e a s]i\s p$agogical defect is likely to exi/ 9 ! developm5t ( our /ud5ts4 ,p>ts ,,iii & ,,iv ( ?is book are publi%$ 9 a sep>ate volume1 z a laboratory manual = qualitative analysis4 ,!y comprise ! in/ructions = laboratory "w introductory to sy/ematic analysis 7! /udy ( reactions & ( ! analysis ( gr\ps1 9 ,"p ,,iii7 & an outl9e = elem5t>y sy/ematic analysis 7,"p ,,iv74 ,! attempt has be5 made1 9 p>ticul>1 to br+ ! laboratory "w1 :i* o!rwise foll[s ! usual l9es ( in/ruction 9 sy/ematic analysis1 also into close/ relations to ! developm5t ( ! sci5tific f\ndations ( analytical *emi/ry1 z repres5t$ 9 ,p>ts ,i & ,,ii4 ,x is believ$ t ! subject matt] l5ds itself especially well to su* a close int]weav+ ( ! two sides ( ! /udy1 )\t any special loss ( "t to ! /ud5t1 & ) ! result1 x is hop$1 ( a greatly increas$ int]e/ on 8 "p & an increas$ /imulus ( ! habit ( sci5tific ?\ght4 ,! foll[+ plan ( "w is us$ by ! au?or ) 8 classes3 ,! fir/ section 7la/+ elev5 weeks7 ( ! c\rse 9 qualitative analysis is />t$ ) "s sev5 to t5 7accord+ to ! ability ( ! class7 lectures or classroom ex]cises1 giv5 daily1 & cov]+ ! fir/ sev5 or ! eight *apt]s ( ,"p ,i4 ,at ! end ( ! second week ! laboratory "w is />t$4 ,dur+ ! rema9d] ( ?is section ( ! c\rse1 two h\rs ( classroom "w & eight h\rs ( laboratory "w p] week are requir$1 &1 9 ?is p]iod1 ,"p ,,iii1 compris+ ! fir/ half ( ! laboratory manual1 is /udi$ 9 ! laboratory 9 close/ connection ) ! classroom "w on ,"p ,,ii ( ! book4 ,z f> z possible1 ! laboratory "w on a giv5 topic prec$es ! classroom "w4 ,?is fir/ c\rse is foll[$ by an elev5 weeks' c\rse 9 sy/ematic analysis1 cov]+ ,"p ,,iv ( ! book4 ,a ?ird 7graduate7 c\rse1 optional = /ud5ts specializ+ 9 *emi/ry1 is (f]$1 9 :i* v complex comm]cial & natural products are analyz$ & 9 :i* special att5tion is also giv5 to r>e elem5ts4 ,dur+ ?is c\rse1 p>ticul> c>e is tak5 to famili>ize /ud5ts ) o!r works on qualitative analysis1 su* z ! outl9es ( ,a4 ,a4 ,noyes & ,bray1 & ! special p>ts ( ,fres5ius's manual4 ,/ud5ts :o h be5 prep>$ 9 g5]al *emi/ry along physico*emical l9es1 z repres5t$1 = in/ance1 by ,smi?'s textbooks1 make m rapid & m easy progress 9 ! fir/ c\rse ?an d /ud5ts o!rwise prep>$4 ,b ! treatm5t ( ! subject is int5d$ to make x possible = /ud5ts1 :o h n paid p>ticul> att5tion to *emical equilibrium & to ! mod]n !ories ( solution 9 _! g5]al *emi/ry c\rse1 to complete ! c\rse )9 ! "t limit indicat$4 ,p]haps "o-?ird ( ! /ud5ts 9 an av]age class1 9 ! pa/1 h tak5 ! c\rse "u ^! conditions & no special difficulty 0 enc\nt]$ by !m4 ,9 ! !oretical treatm5t ! au?or is p>ticul>ly indebt$ to ! orig9al articles & to ! l>g] works ( ,arrh5ius1 van 't ,h(f1 ,n]n/1 ,a4 ,a4 ,noyes1 ,o/wald1 & ,walk]4 ,= ! sy/ematic analytical mat]ial ackn[l$gm5t is due1 9 p>ticul>1 to ,fres5ius's ,qualitative ,*emical ,analysis1 & to ! important publications by ,a4 ,a4 ,noyes & ,bray 9 ! ,j\rnal ( ! ,am]ican ,*emical ,society4 ,"s ( ! excell5t me?ods ( ! latt] au?ors h be5 adopt$ outright1 z indicat$ 9 ! text4 ,= "s special matt]s ! au?or is indebt$ to ! texts ( ,w4 ,a4 ,noyes & ( ,bttg]4 ,con/ant ref]5ces to 8 s\rces ( in=mation h be5 made by ! au?or1 p>tly z a matt] ( ackn[l$gm5t1 & m p>ticul>ly to give /ud5ts & tea*]s ! opportunity = m ext5d$1 fir/-h& read+ on any topic ( int]e/4 ,ref]5ces suitable = college /ud5ts are indicat$ by ! addition ( 7,/ud474 ,9 two or ?ree in/ances1 ! orig9al s\rce ( in=mation has be5 =gott5 & dilig5t se>* has fail$ to trace x4 ,= use 9 prep>+ any future edition ( ! book1 ! au?or w be glad to h 8 att5tion call$ to ! facts by au?ors4 ,! au?or wi%es to express "h 8 p>ticul> appreciation ( ! g5]\s assi/ance giv5 him by 8 =m] colleague1 ,pr(4 ,alex&] ,smi? ( ,columbia ,univ]sity1 ^: sugge/ions & advice1 especially 9 ! edit+ ( ! manuscript & pro(1 h be5 invaluable4 ,he also wi%es to make grateful ackn[l$gm5t to 8 colleagues1 ,pr(s4 ,h4 ,n4 ,mc,coy1 ,h4 ,s*les+]1 & ,dr4 ,edi? ,b>n>d1 to ,pr(4 ,l4 ,w4 ,jones ( ! ,univ]sity ( ,c9c9nati1 ,pr(4 ,e4 ,p4 ,s*o* ( ! ,univ]sity ( ,texas1 ,pr(4 ,b4 ,b4 ,freud ( ,arm\r ,in/itute1 & ,pr(4 ,w4 ,j4 ,hale ( ! ,univ]sity ( ,mi*igan1 :o h assi/$ him by read+ ! pro(s or ! manuscript1 or by c>ry+ out exp]im5tal /udies und]ly+ "p ( ! "w1 or 9 o!r ways4 ,corrections ( 8 mi/akes ( omission & commission1 & sugge/ions1 w be gratefully receiv$ by ! au?or4 ,,julius ,,/ieglitz4 ,,*icago1 ,septemb]1 #aiaa4 ,,cont5ts ,,"p ,i ,,fundam5tal ,,pr9ciples ,,*apt] ,,page ,i4 ,,introduction #c ,,ii4 ,,osmotic ,,pressure ,,& ,,! ,,!ory ,,( ,,solution1 ,i #h ,,iii4 ,,osmotic ,,pressure ,,& ,,! ,,!ory ,,( ,,solution1 ,,ii #ba ,,iv4 ,,! ,,!ory ,,( ,,ionization3 ,,ionization ,,& ,,electrical ,,conductivity #cc ,v4 ,,! ,,!ory ,,( ,,ionization1 ,,ii3 ,,ionization ,,& ,,osmotic ,,pressure2 ,,ionization ,,& ,,*emical ,,activity #fg ,,vi4 ,,*emical ,,equilibrium4 ,,! ,,law ,,( ,,mass ,,action #ij ,,vii4 ,,physical ,,or ,,het]og5e\s ,,equilibrium4--,,! ,,colloidal ,,condition #aah ,,viii4 ,,simultane\s ,,*emical ,,& ,,physical ,,equilibrium4--,,! ,,solubility- ,,or ,,ion-,,product #aci ,,"p ,,ii ,,sy/ematic ,,analysis ,,& ,,! ,,application ,,( ,,fundam5tal ,,pr9ciples ,,ix4 ,,sy/ematic ,,analysis ,,= ,,! ,,common ,,metal ,,ions4 ,,! ,,ions ,,( ,,! ,,alkalies ,,& ,,( ,,! ,,alkal9e ,,e>?s4 ,,ord] ,,( ,,precipitation ,,( ,,difficultly ,,soluble ,,salts ,,) ,a ,,common ,,ion #aeg ,x4 ,,alum9ium2 ,,amphot]ic ,,hydroxides2 ,,hydrolysis ,,( ,,salts4 ,,! ,,alum9ium ,,& ,,z9c ,,gr\ps #aga ,,xi4 ,,! ,,copp] ,,& ,,silv] ,,gr\ps4 ,,precipitation ,,) ,,hydrog5 ,,sulphide #aii ,,xii4 ,,! ,,copp] ,,& ,,silv] ,,gr\ps 7,cont9u$74 ,,! ,,!ory ,,( ,,complex ,,ions #baf ,,xiii4 ,,! ,,ars5ic ,,gr\p4 ,,sulpho-,,acids ,,& ,,sulpho-,,salts #bdb ,,xiv4 ,,oxidation ,,& ,,r$uction ,,reactions1 ,i #bea ,,xv4 ,,oxidation ,,& ,,r$uction1 ,,ii4 ,,oxidation ,,by ,,oxyg51 ,,p]manganates1 ,,etc42 ,,oxidation ,,( ,,organic ,,comp\nds #bgg ,,xvi4 ,,sy/ematic ,,analysis ,,= ,,acid ,,ions #bii ,,li/ ,,( ,,ref]5ces ,,& ,,_! ,,abbreviations ,,note4--7,/ud47 affix$ to a ref]5ce indicates t ! orig9al article is recomm5d$ z suitable read+ = college /ud5ts tak+ _! second ye> ( "w 9 *emi/ry4 ,am4 ,*em4 ,j4--,am]ican ,*emical ,j\rnal4 ,ann4 de ,*im4 et de ,phys4--,annales de ,*imie et de ,physique4 ,b]4 d4 *em4 ,ges4--,b]i*te d] deuts*5 *emis*5 ,gesells*aft4 ,,le ,,blanc',s ,lehrbu* d] ,elektro*emie 7#aijc74 ,b,,ttg]',s ,qualitative ,analyse 7#aijh74 ,compt4 r5d4--,comptes r5dus4 ,,fres5ius',s ,manual ( ,qualitative ,*emical ,analysis 7#aiji74 ,,fres5ius',s ,quantitative ,*emical ,analysis 7#aijd74 ,,van ',t ,,h(f',s ,lectures on ,!oretical & ,physical ,*emi/ry 7#ahih74 ,h4 ,c4 ,,jones',s ,! ,elem5ts ( ,physical ,*emi/ry4 ,j4 ,am4 ,*em4 ,soc4--,j\rnal ( ! ,am]ican ,*emical ,society4 ,j4 ,*em4 ,soc4 7,london74--,j\rnal ( ! ,*emical ,society 7,london74 ,j4 ( ,physiology4--,j\rnal ( ,physiology4 ,j4 ,phys4 ,*em4--,j\rnal ( ,physical ,*emi/ry4 ,j4 prakt4 ,*em4--,j\rnal fr praktis*e ,*emie4 ,,kohlraus* ,,und ,,holborn',s ,leitv]mg5 d] ,elektrolyte 7#ahih74 ,,l&olt-,b,,rn/e9-,,mey]h(f]',s ,physikalis*-,*emis*e ,tabell54 ,liebig's ,ann4--,liebig's ,annal5 d] ,*emie4 ,,n]n/',s ,!oretical ,*emi/ry 7#aijd74 ,,n]n/',s ,!oretis*e ,*emie 7#aiji74 ,,o/wald',s ,lehrbu* d] allgeme95 ,*emie 7#ahic74 ,,o/wald',s ,sci5tific ,f\ndations ( ,analytical ,*emi/ry 7#aijh74 ,,o/wald',s ,wiss5s*aftli*e ,grundlag5 d] analytis*5 ,*emie 7#ahid74 ,phil4 ,mag4--,philosophical ,magaz9e4 ,phil4 ,trans4 ,royal ,soc4--,philosophical ,transactions ( ! ,royal ,society4 ,pogg5dorff's ,ann4--,pogg5dorff's ,annal5 d] ,physik und ,*emie4 ,proc4 ,am4 ,acad4--,proce$+s ( ! ,am]ican ,academy4 ,,rems5',s ,inorganic ,*emi/ry1 ,advanc$ ,c\rse1 #aijd4 ,,smi?',s ,g5]al ,inorganic ,*emi/ry 7#aiji74 ,,smi?',s ,g5]al ,*emi/ry = ,colleges 7#aijh74 ,,treadwell',s ,qualitative ,analyse 7#aijb74 ,,walk]',s ,introduction to ,physical ,*emi/ry 7#aiji74 ,wi$emann's ,ann4--,wi$emann's ,annal5 d] ,physik und ,*emie4 ,z4 analyt4 ,*em4--,zeits*rift fr analytis*e ,*emie4 ,z4 anorg4 ,*em4--,zeits*rift fr anorganis*e ,*emie4 ,z4 fr ,elektro*em4--,zeits*rift fr ,elektro*emie4 ,z4 phys4 ,*em4--,zeits*rift fr physikalis*e ,*emie4 ,,qualitative ,,*emical ,,analysis ,,"p ,i ,,fundam5tal ,,pr9ciples ,,*apt] ,i ,,introduction ,qualitative *emical analysis is conc]n$ ) ! det]m9ation ( ! k9ds ( matt] pres5t 9 any giv5 sub/ance4 ,9 its broade/ s5se x includes ! det]m9ation ( all k9ds ( matt]1 ! elem5ts1 r>e z well z common1 & all _! comb9ations1 organic comp\nds z well z inorganic4 ,! recognition ( ! pres5ce ( r>e elem5ts1 su* z radium1 uranium1 ?orium1 tung/51 c]ium1 etc41 is becom+ a matt] ( gr[+ importance ) ! mod]n developm5t ( ! subject ( radioactivity & ! te*nical exploitation ( ! r>] elem5ts1 & x is a common exp]i5ce = an analytical *emi/ to be call$ ^u to det]m9e ! pres5ce or abs5ce ( alcohol 9 bev]ages1 ( =mal9 9 milk or o!r foods1 & n a r>e exp]i5ce to be oblig$ to make te/s = ! pres5ce ( alkaloids l /ry*n9e1 morph9e1 coca9e1 or = ! pres5ce ( num]\s o!r organic comp\nds4 ,9 ?is book1 h[ev]1 we %all limit our mat]ial to ! m common elem5ts & _! mo/ important inorganic comb9ations1 includ+ only a few typical organic acids4 ,! limitation ( our exp]im5tal mat]ial w make x possible to devote special att5tion to ! sci5tific pr9ciples und]ly+ analysis1 to secure a cle> & def9ite grasp ( !m1 & to imp>t ) simple mat]ial su* exp]i5ce 9 ! te*nique & me?ods ( analysis z w tra9 ! /ud5t to apply bo? 8 !oretical & practical k to any field ( analysis occasion may require4 ,accurate qualitative analysis1 p#jjd 9 any field1 w dep5d on ! c>e tak5 9 ma/]+ ! !oretical significance & ! te*nique ( ! me?ods recomm5d$ = ! specific problem be=e ! analy/2 ! details ( ! me?ods !mselves1 9 any problem involv+ m ?an elem5t>y analysis1 are s\ght & f\nd by him z a matt] ( practice 9 suitable l>g] works1 9 monographs & 9 ! orig9al lit]ature4 ,) ! object ( sugge/+ ?is broad] application ( ! tra9+ acquir$ & ( cultivat+ ! invaluable habit ( ! pr(essional *emi/ ( consult+ l>g] works & ! lit]ature1 frequ5t ref]5ce w be made to su* l>g] works1 & to orig9al pap]s 9 :i* m special subjects ( analysis or !ory are elaborately treat$4 ,to recognize1 9 a sub/ance1 ! pres5ce ( any elem5t or comp\nd1 "o mu/ "k its *>act]i/ic reactions1 :i* w make x possible to di/+ui% x f all o!r elem5ts or comp\nds4 ,fur!r1 9 ord] to rea* conclusions ) ! greate/ possible spe$1 directness1 & conclusiv5ess1 x is usually be/ to c>ry out an exam9ation 9 "s sy/ematic way1 r ?an 9 a haphaz>d & irregul> fa%ion4 ,we di/+ui%1 accord+ly1 two p>ts 9 our laboratory "w3 fir/1 ! /udy ( *>act]i/ic te/s or reactions ( ! common elem5ts & su* ( _! comp\nds z are ( importance 9 elem5t>y analysis 7,"p ,,iii71 &1 secondly1 practice 9 a sy/ematic me?od ( analysis 7,"p ,,iv74 ,9 ! /udy ( ! reactions1 ! way w be pav$ = sy/ematic analysis1 by tak+ ! elem5ts 9 ! gr\ps1 :i* =m ! basis ( ! sy/em ( analysis employ$1 & by analyses ( mixtures ( ! elem5ts ( a gr\p imm$iately aft] ! gr\p has be5 /udi$4 ,reliable & intellig5t analysis is possible only ) a cle> k ( ! *emi/ry ( ! reactions us$1 & ! *emi/ry ( ! mo/ important typical reactions w !re=e be consid]$ 79 ,"p ,,ii71 simultane\sly ) ! laboratory /udy ( ! reactions & ( sy/ematic analysis4 ,! reactions = id5tify+ an elem5t or comp\nd mu/ br+ physical evid5ce :i* c be recogniz$ by our s5ses4 ,! s5se ( t\* is sc>cely ev] appeal$ to2 p]haps ! numbness or p>alysis ( ! s5se ( t\* imp>t$ to ! tongue or eyelid by ! alkaloid coca9e & a few mod]n sub/itutes = x1 & ! t+l+ s5sation produc$ on ! tongue p#jje by aconite & its prep>ations1 are ! mo/ important1 b r>e1 in/ances ( an appeal to ?is s5se 9 analytical "w4 ,! s5se ( ta/e is also r>ely us$1 & always ) ! greate/ c>e to prev5t poison\s effects4 ,acids & bases1 bitt] alkaloids1 su* z /ry*n9e & bruc9e1 sweet sub/ances1 su* z cane sug>1 glucose1 glyc]9e1 are in/ances ( comp\nds :i* affect our s5se ( ta/e4 ,9 all ^! cases ! ta/e is us$ r z a confirmative te/ ?an z a conclusive pro( ( ! id5tity ( a suspect$ sub/ance4 ,! s5se ( smell is r m useful 9 qualitative analysis ?an t ( ta/e or ( t\*4 ,hydrog5 sulphide & ammonia1 unless pres5t 9 traces only1 readily reveal !mselves by _! odor4 ,e *emi/ %\ld be famili> ) ! fa9t b v *>act]i/ic odor ( hydrocyanic acid1#a :i* %\ld in/antly & automatically w>n him ( ! pres5ce ( ?is pot5t poison4 ,ow+ to p>tial decomposition by ! moi/ure & c>bonic acid absorb$ f ! atmosph]e1 alkali cyanides also give ?is important w>n+ signal4 ,te/s bas$ on ! odors ( comp\nds are p>ticul>ly valuable 9 ! field ( organic *emi/ry1 :]e ! s5se ( smell is ext5sively us$ = qualitative purposes2 = in/ance1 ! pleasant smell ( acetic e/]1 & ! nauseat+ odor ( an organic ars5ic d]ivative1 cacodyl oxide1 may be us$ ) advantage 9 id5tify+ acetic acid4 ,b ! evid5ce ( t\*1 ta/e1 & smell is1 on ! :ole1 only occasionally available 9 *emical analysis--almo/ all ! te/s employ$ are visual ones4 ,a small proportion ( ^! are color te/s4 ,! color ( iod9e vapor or ( ! solution ( iod9e 9 *lor(orm1 ! colors ( metallic copp] or gold1 ( copp] salts 9 ammoniacal solutions1 ( sulphides1 su* z ! orange sulphide ( antimony 7exps471 may be m5tion$ z in/ances1 9 :i* a te/ ( id5tity dep5ds on ! obs]vation ( "s *>act]i/ic color4 ,b ! great majority ( analytical te/s dep5d on obs]vations ( *anges ( /ate2 evid5ce consi/+ 9 ! solution ( solids1 ! =mation ( precipitates1 ! evolution ( gases1 =ms ! mo/ important "p ( ! obs]vations1 p#jjf on :i* our conclusions are bas$4 ,9 organic *emi/ry1 det]m9ations ( melt+-po9ts & ( boil+-po9ts1 :i* are v commonly us$ = ! qualitative id5tification ( comp\nds1 =m fur!r in/ances ( ! application1 to qualitative purposes1 ( obs]vations bas$ on *anges ( /ate4 ,9 v _m cases1 :]e ! =mation or non=mation ( a precipitate is int5d$ to be us$ z an indication ( ! pres5ce or abs5ce ( a giv5 sub/ance1 ! precipitat+ ag5t may ?r[ d[n "o or m ( sev]al diff]5t precipitates1 :i*1 se5 )\t ! aid ( a microscope1 _c be id5tifi$ )\t fur!r exam9ation4 ,x is1 ?us1 commonly necess>y to use a sequ5ce ( su* te/s = ! complete id5tification4 ,= in/ance1 ! addition ( hydro*loric acid to a solution ( lead1 m]cur\s or silv] nitrate w produce a :ite precipitate4 ,! precipitates may be di/+ui%$ by a fur!r exam9ation ( _! solubilities3 hot wat] w dissolve ! lead *loride1 ammonia readily dissolves ! *loride ( silv] & conv]ts ! m]cur\s *loride into a black insoluble mixture conta9+ f9ely divid$ m]cury 7exps474 ,by ! same means ! *lorides1 if pres5t toge!r1 may be sep>at$ f "o ano!r & subsequ5tly id5tifi$4 ,sy/ematic analysis consi/s v l>gely 9 ! use ( a prop]1 logical sequ5ce ( su* precipitation & solution reactions1 & 9 ! draw+ ( def9ite conclusions f ! results obta9$4 ,by f> ! greate/ "p ( ! exp]im5tal "w 9 qualitative analysis has to d1 !n1 ) solution & precipitation4 ,= intellig5t & accurate analytical "w a cle> k ( ! nature ( solution &1 9 p>ticul>1 ( ! simple laws gov]n+ *emical action 9 solution1 & ( ^? gov]n+ ! =mation & ! solution ( precipitates1 is indisp5sable4 ,! discov]ies ( van 't ,h(f1 9 #ahhe-h1 conc]n+ ! nature ( solution1 & ! subsequ5t discov]ies ( ,arrh5ius1 ,n]n/1 ,o/wald & o!rs1 h advanc$ e bran* ( *emi/ry1 b p]haps no bran* has pr(it$ q s mu* z ! !ory ( analytical *emi/ry1 :i*1 z a result ( ^! discov]ies1 = ! fir/ "t1 receiv$ a cle>1 precise & satisfy+ sci5tific =mulation ( its empirical processes4#b p#jjg ,on acc\nt ( ! fundam5tal importance ( ?is mod]n sci5tific =mulation ( ! pr9ciples ( analytical *emi/ry = ! prop] und]/&+ ( our subject1 we %all consid] fir/ 79 ,"p ,i7 ! mod]n !ories ( solution1 ) _! exp]im5tal f\ndations1 & we %all !n develop ! simpl] fundam5tal laws gov]n+ *emical action & physical *anges 9 solution4 ,! analytical reactions !mselves w be utiliz$ z f> z possible z ! mat]ial = develop+ ^! g5]al pr9ciples1 s t ?is /udy may lead to ! desir$ grasp ( ! !ory ( analysis & yet1 at ! same "t1 advance ! /ud5t's k ( ! practice ( analysis4 ,,footnotes3 #a ,on acc\nt ( ! poison\s "* ( ?is & o!r vapors1 ! vessel conta9+ a sub/ance ^: odor "o wi%es to te/ is n br\ght to ! nose1 b a little ( ! vapor is c>efully waft$ t[>ds "o by a motion ( ! h&1 ! vapor be+ ?us greatly dilut$ ) air4 #b ,we owe ! fir/ mod]n sci5tific treatm5t ( ! pr9ciples ( ,analytical ,*emi/ry to ,o/wald's ,wiss5s*aftli*e ,grundlag5 d] analytis*5 ,*emie1 #ahid4 p#jjh ,,*apt] ,,ii ,,osmotic ,,pressure ,,& ,,! ,,!ory ,,( ,,solution ,i ,if a conc5trat$ solution ( a sub/ance l sug> or cupric nitrate is all[$ to fl[ into a cyl9d] ( wat] 7exp4 ) cupric nitrate71 we f9d t ! outside =ces--gravity--t5d to draw ! solution1 ^: specific gravity is great] ?an t ( wat]1 to ! bottom ( ! cyl9d]4 ,9 ?is me?od ( proce$+ !re is "s inevitable mix+ ( ! solution ) ! solv5t1 z ! result ( friction1 b ! ma9 portion ( ! deep blue solution is drawn to ! bottom ( ! vessel & =ms a blue lay] "u ! colorless wat]4 ,a mu* %>p] l9e ( sep>ation may be obta9$ by all[+ ! cupric nitrate solution to ent] a cyl9d] ( wat] f "u ! wat] 7see ,fig4 #a71 ! great d5sity ( ! nitrate solution caus+ x to displace ! wat] )\t p]ceptible mix+ ( ! two liquids 7exp474 ,if ^! vessels are left at re/1 x may be not$1 f day to day1 t ! copp] nitrate diffuses fur!r & fur!r into ! pure solv5t1 & c>eful exam9ation w\ld %[ t ! solv5t1 9 turn1 diffuses also into ! copp] nitrate solution4 ,! process is a v sl[ "o1 b x w cont9ue until a solution ( uni=m conc5tration is rea*$1 & ?is w be ! case1 :atev] ! %ape ( ! vessel may be4 ,if1 = ! mom5t1 only ! copp] nitrate be consid]$--& :at we are develop+ = ! copp] nitrate may be appli$ equally well1 mutatis mut&is1 to ! diffusion ( wat] into ! copp] nitrate solution--x is obvi\s !n t copp] nitrate 9 solution diffuses 9 all directions1 ev5 aga9/ ! =ce ( gravity1 & x is pla9 also1 t any object1 resi/+ or arre/+ su* a motion ( mat]ial p>ticles1 mu/ h a =ce or pressure ex]t$ ^u x4 ,:atev] ! ultimate p#jji cause ( ! motion1 :e!r x is ! result ( inh]5t molecul> velocities ( ! dissolv$ copp] nitrate1 or ( an attraction betwe5 ! solute & ! solv5t1 or bo?1 x is inevitable t a pressure mu/ result f ! impact ( ! mov+ solute aga9/ ! solv5t4#c ,illu/ration3 ,,fig4 #a4 ,we h ?us ph5om5a ( diffusion ( solutes ?r\gh solv5ts1 exactly z we h ! well-kn[n diffusion ( gases1 & ! two ph5om5a are unque/ionably v mu* alike1 ! solute1 l ! gas1 t5d+ to diffuse f ! place ( high]1 to t ( l[] conc5tration4#d ,likewise1 if a solution ( uni=m conc5tration is heat$ 9 "o "p & n 9 ano!r1 ! solute1#d l a gas "u simil> conditions1 w move f ! w>m] to ! cold] "p ( ! solution1 z 0 demon/rat$ by ,soret4#e ,)\t committ+ ourselves = ! pres5t to any giv5 reason = ! diffusion1 we note t ! t5d5cy to diffusion is a fact1 & we mu/ accept ! conclusion t e ob/acle to su* diffusion mu/ h a pressure ex]t$ ^u x4 ,n[1 if a solution is sep>at$ f ! pure solv5t by means ( a s-call$ semip]meable membrane1 "s ( ! results ( ?is t5d5cy to diffusion may be demon/rat$4 ,,exp4 ,a conc5trat$ solution ( cane sug> 9 wat]1 color$ ) "s anil9e dye1 is enclos$ 9 a ?imble ( p>*m5t pap] firmly fa/5$ to a long n>r[ glass tube 7see ,fig4 #b7 & ! cell is plac$ 9 a vessel ( pure wat]4 ,! p>*m5t is n absolutely semip]meable1 b x is approximately s1 all[+ ! solv5t1 wat]1 to pass1 b be+ practically imp]vi\s to ! solute sug>4 ,a ,s*lei*] & ,s*ll diffusion-?imble1 ,no4 #egi1 may be us$1 ) advantage1 z ! ?imble4 7,cf4 ,smi?'s ,introduction to ,inorganic ,*emi/ry1 p4 #bhd47 p#jaj ,we obs]ve1 pres5tly1 t ! sy/em is n 9 a condition ( equilibrium2 wat] passes ?r\gh ! ?imble into ! sug> solution & ! latt] exp&s1 produc+ a decid$ diff]5ce ( level1 & consequ5tly a hydro/atic pressure1 betwe5 ! liquid 9 ! cell & ! solv5t outside ( x4 ,we may note two facts3 fir/1 t ! *ange includes an expansion ( ! solute1#f ! sug>1 9 ! solution--t is1 ! t5d5cy ( ! solute to exp& into l>g] volumes ( ! solv5t is satisfi$ exactly z 9 ! exp]im5t 7,fig4 #a7 describ$ above4 ,9 ! second place1 l all natural ph5om5a :i* proce$ spontane\sly1 ! *ange is 9 ! direction ( equilibrium2 = :5 ! hydro/atic pressure on ! solution 9 ! cell becomes suffici5tly great1 or if x is made suffici5tly great at once by ! application ( "s outside pressure1 a po9t ( equilibrium is rea*$1 at :i* wat] w pass nei!r into ! cell nor out ( x4 ,at t po9t1 ! t5d5cy to expansion1 bo? ( ! solute & ( ! solv5t 9 ! solution1 is j ov]come by ! pressure on ! solution4 ,illu/ration3 ,,fig4 #b4 ,def9ition ( ,osmotic ,pressure4--,! hydro/atic pressure :i* is necess>y to br+ ! solution into equilibrium ) ! pure solv5t1 :5 ! two are sep>at$ by a semip]meable membrane1 may be def9$1 accord+ to van 't ,h(f1 z ! measure ( :at is call$ ! osmotic pressure ( ! solution4 ,we note t ?is def9ition /ill does n commit u to any !ory z to ! orig9 ( ! pressure1 b m]ely =mulates an exp]im5tal relation4 ,measurem5t ( ,osmotic ,pressure4--,m p]fect semip]meable membranes c be produc$4 ,^! make possible quantitative measurem5ts ( ! hydro/atic pressure on a solution1 :5 equilibrium betwe5 ! solution & ! pure solv5t p#jaa has be5 rea*$4 ,su* membranes 7 fir/ us$ by ,pfeff]4 ,!y consi/ ( c]ta9 gelat9\s precipitates1 notably copp] f]rocyanide4 ,films ( ^! precipitates may be =m$1 "u prop] conditions1 :i* are p]meable to wat] b n to c]ta9 solutes1 su* z cane sug>1 glucose & galactose4 ,illu/ration3 ,,fig4 #c4 ,by precipitat+ ^! membranes 9 ! pores ( unglaz$ clay cells1 especially by ! process devis$ by ,morse1#g we may make !m suffici5tly /rong to resi/ enorm\s pressures--"s us$ by ! ,e>l ( ,b]keley 7 f\nd to )/& a pressure ( #acj atmosph]es4 ,! hydro/atic pressure requir$ to produce equilibrium may !n be measur$ 9 ei!r ( two ways4 ,! fir/ me?od1 us$ orig9ally by ,pfeff] & m rec5tly by ,morse & ,fraz]#h & _! collaborators 9 a wond]fully consci5ti\s /udy ( osmotic pressures1 consi/s 9 all[+ ! hydro/atic pressure to e/abli% itself by ! passage ( v small quantities ( ! solv5t1 ?r\gh ! membrane1 into ! tightly clos$ cell conta9+ ! solution4 ,:5 ! result+ pressure produces a condition ( equilibrium1 x is measur$#i by a manomet] connect$ ) ! solution1 mu* z a gas pressure may be measur$ 7,fig4 #c74aj ,?is process requires consid]able "t = exact measurem5ts--weeks1 dur+ :i* ! cell mu/ be kept at a con/ant temp]ature4 ,! second me?od1 :i* has be5 us$ by ,b]keley & ,h>tley1#aa is v mu* m rapid & requires only a few h\rs = ! measurem5t4 ,x consi/s 9 hav+ ! pure solv5t )9 ! cell1 in/ead ( outside ( x1 & 9 p#jab ex]t+ an ext]nal pressure on ! solution outside ( ! cell1 until a delicate manomet]1 communicat+ ) ! pure solv5t1 %[s t wat] does n pass ?r\gh ! membrane 9 ei!r direction--equilibrium hav+ be5 rea*$4 ,osmotic ,pressure & ! ,laws ( ,gases4--,! "w ( van 't ,h(f1 :i* has prov$ ( ine/imable value to ! developm5t ( *emi/ry1 succe$$ 9 demon/rat+ t1 = dilute solutions1 ! osmotic pressure1 z def9$ above1 obeys ! common laws ( gases1#ab--t1 9 fact1 a sub/ance 9 a dilute solution has an osmotic pressure equal to ! gas pressure :i* x w\ld ex]t if x 7 a gas ( ! same volume & at ! same temp]ature4#ac ,space does n p]mit ! pres5tation ( all ! details ( ! evid5ce confirm+ ?is conclusion1 b "s ( ! mo/ direct exp]im5tal pro(s#ad w be consid]$4 p#jac ,boyle's ,law4--,boyle's law = gases /ates t1 at a con/ant temp]ature1 ! pressure ( a gas *anges inv]sely z its volume1 or directly z its conc5tration4 ,ma!matically we h ,p 3 ,p ,v 3 ,v or ,p ,v ,p ,v a con/ant1 & ,p 3 ,p ,c 3 ,c or ,p 3 ,c ,p 3 ,c a con/ant4 ,:5 van 't ,h(f publi%$ 8 fir/ pap] on ! subject1 ,pfeff]'s results f ! direct measurem5t ( ! osmotic pressures ( cane-sug> solutions 7 available1 & ev5 ^!1 al?\gh exp]im5tally n z exact z m rec5t det]m9ations1 %[$ pla9ly t1 at a giv5 temp]ature1 ! osmotic pressure ( a sug> solution v>ies directly z ! conc5tration1 or inv]sely z ! volume conta9+ a giv5 weight ( ! sug>4 ,at #ac-af we h3 ,conc5tration4 ,osmotic ,pressure4 ,pressure_/ mm4 ,m]cury4 ,conc5tration4 #a4jj #ece #ece #b4jj #ajaf #ejh #b4gd #aeah #eed #d4jj #bjhb #eba #f4jj #cjge #eac ,! ratio ( pressure to conc5tration v>ies irregul>ly r\nd a mean value ( #ebf1 & is approximately con/ant4 ,! m rec5t1 exce$+ly c>eful measurem5ts ( ,morse & ,fraz] confirm ! conclusion1 t ,boyle's law holds = ! osmotic p#jad pressures ( dilute solutions2 !y f9d t ! osmotic pressures ( glucose & ( cane-sug> solutions v>y directly z ! conc5trations ( ! solutions1 at a con/ant temp]ature4#ae ,gay-,lussac's ,law4--,gay-,lussac's law = gases /ates t1 if ! volume ( gas is kept con/ant1 its pressure increases by #a _/ #bgc ( its value = e degree above #j ,c41 or ,pt ,p#j 7#a t _/ #bgc74 ,express+ ! temp]ature 9 absolute degrees1 we h m simply3 ,pt ,p#j 7,t _/ #bgc7 or ,pt _/ ,t ,p#j _/ #bgc a con/ant4#af ,t is1 ! pressure ( a gas v>ies directly z its absolute temp]ature1 if ! volume is kept con/ant4 ,pfeff]'s results1 on ! osmotic pressure ( sug> solutions at diff]5t temp]atures1 7 n suffici5tly accurate to enable van 't ,h(f to use !m to confirm positively ! rigor\s !rmodynamic pro( 7footnote #c1 p4 #ab71 t ! osmotic pressure mu/ increase proportionally to ! absolute temp]ature1 z requir$ by ,gay-,lussac's law4 ,b ! data did %[1 uni=mly1 a m>k$ increase ( ! osmotic pressure ) ! temp]ature &1 frequ5tly1 excell5t agreem5t betwe5 !ory & exp]im5t4 ,m /rik+ 7 ! results obta9$ by van 't ,h(f 9 te/+ ! correctness ( ?is ext5sion ( ,gay-,lussac's law by means ( ,soret's results on ! diffusion ( a solute f a w>m] to a cold] place4 ,x 0 f\nd t ! conc5trations1 obta9$ by ,soret :5 equilibrium 0 rea*$1 agre$ closely ) ! dem& t ! osmotic pressures 9 ! cold] & ! w>m] p>ts ( ! solution %\ld be equal1 & t ! osmotic pressure ( a giv5 weight ( solute 9 a giv5 volume %\ld increase proportionally to ! absolute temp]ature4 ,an elevation ( temp]ature1 9 a portion ( a uni=m solution1 w increase ! osmotic pressure ( ?is "p4 ,diffusion w foll[1 until ! loss 9 conc5tration ( ! solute1 & !re=e ! loss ( osmotic pressure 7,boyle's law71 ( ! w>m] "p1 & ! increas$ conc5tration & increas$ pressure ( ! cold] portion result 9 all p>ts ( ! solution hav+ ! same osmotic pressure4 p#jae ,z an example1 a conc5tration ( #ag4cc copp] sulphate at #bj 0 f\nd to be 9 equilibrium ) a conc5tration ( #ad4jc at #hj4 ,n[1 if ! #ag4cc solution _h an osmotic pressure ( ,p mm4 at #bj1 a #ad4jc solution at ! same temp]ature w\ld h a pressure ( 7#ad4jc _/ #ag4cc7 ,p mm4 7,boyle's law71 & ?is w\ld increase to 7#ad4jc _/ #ag4cc7 ,p 7#cec _/ #bic7 mm4 at #hj ,c41 or #j4ige ,p mm4--a result %[+ t ! osmotic pressure 9 ! hot "p 0 practically ! same z t1 7,p71 9 ! cold "p ( ! solution4#ag ,x is a s\rce ( great satisfaction1 t ! rec5t v exact & pa9/ak+ "w ( ,morse & ,fraz]1#ah 9 measur+ osmotic pressures directly1 completely confirms ?is fundam5tally important conclusion1 t ! osmotic pressure ( a solution does increase proportionally to its absolute temp]ature4 ,! ,avogadro-van 't ,h(f ,hypo!sis4--,= *emi/s1 ! mo/ important "p ( van 't ,h(f's "w lies 9 ! ext5sion ( ! ,avogadro ,hypo!sis to solutions4 ,z van 't ,h(f expresses x1 equal volumes ( ! mo/ diff]5t solutions1 hav+ ! same osmotic pressure & ! same temp]ature1 conta9 ! same numb] ( dissolv$ molecules1--t numb]1 namely1 :i* w\ld be f\nd 9 ! same volume ( a gas at ! same gas pressure & temp]ature4#ai p#jaf ,pfeff]'s measurem5ts1 ) solutions ( #a g4 ( sug> 9 #ajj c4c4 ( wat] 7! volume ( ! solution is #ajj4f c4c471 7 %[n to prove1 t ! obs]v$ osmotic pressures agre$ excell5tly ) ! gas pressures1 calculat$ = ! equimol> weight ( hydrog51 9 ! same volume & at ! same temp]ature3 ,osmotic ,pressure ,temp]ature4 ,f\nd4 ,calculat$4#bj ,atmosph]e4 ,atmosph]e4 #f4h #j4ffd #j4ffe #ac4g #j4fia #j4fha #ad4b #j4fga #j4fhb #ae4e #j4fhd #j4fhf #bb #j4gba #j4gja #cb #j4gaf #j4gbe #cf #j4gdf #j4gce ,morse's m rec5t & m exact results %[1 t ! osmotic pressure ( solutions ( cane sug> & ( glucose 7correct$ = ! volume occupi$ by ! sug>1 see footnote1 p4 #ae7 agrees )9 #f ) ! values dem&$ by van 't ,h(f's !ory1 be+ ab\t #f l>g] = conc5trations rang+ f #j4a to #a4j mol>4 ,! diff]5ce ( #f is notewor?y & is probably due to second>y causes1 b sugge/s ext5d$ inve/igation ( its s\rce4 ,indirect ,det]m9ations ( ,osmotic ,pressure4--,! exp]im5tal results giv5 h be5 obta9$ by direct measurem5ts ( osmotic pressures ) ! aid ( semip]meable membranes4 p#jag ,p]fect membranes are v difficult to prep>e1 & membranes ( ?is k9d c be us$ only ) a few solutes4 ,nature (f]s u1 h[ev]1 =ms ( semip]meable walls betwe5 solutions & pure solv5ts1 :i* 9 _m in/ances are p]fect4 ,! atmosph]e1 above a volatile pure solv5t & a solution ( a nonvolatile sub/ance 9 t solv5t1 :5 bo? liquids are plac$ side by side 9 a clos$ space1 w\ld s]ve z a semip]meable wall3 ! solv5t vaporizes & may pass freely f solv5t to solution & vice v]sa1 b ! solute1 9 ! case "u consid]ation1 is nonvolatile & !re=e _c pass ?r\gh ! atmosph]e4 ,! vapor pressure ( a pure solv5t be+ always f\nd to be high] ?an t ( a solution 9 ?is solv5t1 at ! same temp]ature1 ! solv5t w\ld pass 9 su* a clos$ space z vapor f ! pure solv5t & w\ld cond5se 9 ! solution2 x !reby dilutes ! solution & ! solute1 & ! solv5t 9 ! solution1 exp&1 exactly z 9 ! absorption ( a solv5t by a solution ?r\gh a semip]meable membrane4 ,aga91 ! vapor pressure ( a solution be+ l[] ?an t ( ! pure solv5t1 ! solution 7( a nonvolatile solute7 mu/ be heat$ high] ?an ! pure solv5t1 to br+ bo? to ! boil+-po9t2 t is1 !re is an elevation ( ! boil+-po9t1 :5 a nonvolatile solute is dissolv$ 9 a solv5t4 ,! solute be+ nonvolatile1 only ! solv5t passes (f 9 ! process ( boil+1 ! solute becomes m conc5trat$1 &1 accord+ to van 't ,h(f's ext5sion ( ,boyle's law1 ! osmotic pressure ( ! solution increases4 ,simil>ly1 :5 a solution is cool$ until freez+ occurs1 provid$ ! solute does n cry/allize out ) ! solv5t1 ! conc5tration ( ! solute is aga9 increas$1 & !re=e ! osmotic pressure ( ! solution is also increas$4 ,van 't ,h(f recogniz$ ! relations exi/+ betwe5 ! freez+1 boil+ & vaporization ( solutions1 on ! "o h&1 & ! *anges ( _! osmotic pressures on ! o!r4 ,by develop+ rigor\sly ! relations betwe5 ! l[]+ ( ! vapor t5sion1 ! rais+ ( ! boil+-po9t1 ! l[]+ ( ! freez+-po9t ( a solv5t by a solute & ! osmotic pressure ( ! solution1 he made x possible#ba to use p#jah ext5sive exp]im5tal mat]ial1#bb on ! elevation ( boil+-po9ts & ! l[]+ ( freez+-po9ts & ( vapor t5sions1 to det]m9e ! osmotic pressures ( solutions4 ,! !ory ( ! relation ( osmotic pressure to gas pressure is fully confirm$ by ^! measurem5ts1 = ^? cases to :i* x may prop]ly be appli$1 namely1 to suffici5tly dilute solutions & su* z h only negligible heats ( dilution1 i4e4 9 :i* dilution does n involve *emical *anges4 ,app>5t ,exceptions4--,in/ead ( discuss+ ! va/ am\nt ( mat]ial ( ?is k9d1 :i* agrees ) van 't ,h(f's !ory1 we may consid]1 m pr(itably1 typical cases ( app>5t exceptions4 ,! mo/ important in/ance ( ?is k9d1 ! case ( solutions ( comp\nds :i* und]go electrolytic dissociation or ionization1 w be sep>ately discuss$ 9 ! next *apt]1 & we %all f9d t van 't ,h(f's great g5]alization is a vital elem5t 9 ! evid5ce ( ?is important =m ( dissociation4 ,( o!r app>5t exceptions1 we may note ! fact t "s solutes seem to give abnormally l[ osmotic pressures#bc 9 c]ta9 solutions4 ,= in/ance1 b5zoic acid1 9 b5z5e solutions1 gives only a little m ?an half z great an osmotic pressure z x does 9 aque\s solutions ( ! same conc5tration & temp]ature1 & z w\ld be calculat$ on ! basis ( ! ,avogadro-van 't ,h(f ,hypo!sis = a comp\nd ( ! =mula ,c#f;,h#e;,,cooh & ! molecul> weight #abb4 ,b a rigor\s /udy#bd ( ! di/ribution ( b5zoic acid betwe5 wat] & b5z5e1 :5 solutions ( ! acid 9 ! two solv5ts are %ak5 toge!r until equilibrium is e/abli%$ 7,*apt] ,,viii71 has prov$ t ! di/ribution is /rictly 9 accord ) ! assumption t b5zoic acid1 9 aque\s solution1 has ! molecul> weight #abb & ! composition ,c#f;,h#e;,,cooh1 & t1 9 b5z5e solution1 x has ! molecul> weight #bdd & ! composition 7,c#f;,h#e;,,cooh7#b2 only a small "p ( ! acid 7,c#f;,h#e;,,cooh7#b is decompos$ 9 b5z5e solution into ! simpl] molecules1 ( ! composition ,c#f;,h#e;,,cooh4 ,9 o!r words1 ! simpl] molecules ,c#f;,h#e;,,cooh are polym]iz$ or associat$ to =m l>g] molecules 9 b5z5e solution1 mu* z ! gas nitrog5 dioxide ,,no#b goes ov] m or less into ! gas ,n#b,o#d1 especially at l[ temp]atures1 & z hydrog5 fluoride at l[ temp]atures has ! composition ,h#b;,f#b1 :ile at high] temp]atures x is ,,hf4 ,! div]g5ce ( ! b5z5e solutions ( b5zoic acid f ! ,avogadro-van 't ,h(f pr9ciple is !re=e only an app>5t "o1 n a real "o1 inasmu* z ! osmotic pressure ( ! solutions agrees p]fectly ) t calculat$ = solutions ( a sub/ance 7,c#f;,h#e;,,cooh7#b1 ( molecul> weight #bdd4 ,su* associat$ molecules 7( organic acids1 alcohols1 ph5ols1 etc47 occur p#jai p>ticul>ly readily 9 liquids ( small dissociat+ p[]1 l b5z5e1 & su* solutions %[ m>k$ absorption ( heat on dilution1#be ! dilution be+ accompani$ by a *emical *ange4 ,! associat$ molecules are dissociat$ m & m completely 7,c#f;,h#e;,,cooh7#b #b ,c#f;,h#e;,,cooh1 ev5 9 ^! solv5ts1 z ! solutions are dilut$4 ,s9ce dilution results 9 a *emical increase 9 ! numb] ( molecules1 ! osmotic pressure _c decrease proportionally ) ! increase ( volume 9 su* a case z ?is4 ,nor does gas pressure1 x mu/ be rememb]$1 decrease proportionally to ! volume 9 ! case ( gases :i* %[ *emical *anges ) *ange ( volume1 e4g4 9 ! case ( nitrog5 tetroxide1 = :i* we h ,n#b,o#d #b ,,no#b4 ,9 /ill o!r in/ances1 app>5tly too high osmotic pressures1 or too l[ molecul> weights1 h be5 f\nd by ! application ( ! ,avogadro-van 't ,h(f ,hypo!sis to solutions3 = in/ance1 ! molecul> weight ( sodium1 :5 dissolv$ 9 m]cury1 0 f\nd by ,ramsay to v>y f #ba4f1 9 dilute1 to #ae4a 9 conc5trat$ solutions4 ,b ,cady f\nd t ! heat ( dilution ( sodium 9 m]cury solution is consid]able1 & by tak+ ?is prop]ly into acc\nt1 ,bancr(t 0 able to %[ t ! molecul> weight1 correctly calculat$ 9 a giv5 exp]im5t1 is #bb4g 7agree+ well ) ! !oretical weight #bc71 9 place ( #af4e1 z calculat$ )\t mak+ ! requir$ all[ance = ! heat ( dilution4#bf ,^! det]m9ations are mo/ in/ructive 9 %[+ t ! s\rces ( "s ( ! mo/ important deviations f ! van 't ,h(f-,avogadro pr9ciple1 deviations :i* h be5 br\ght =w>d z argum5ts aga9/ its assumptions1 are due1 n to any untru/wor?9ess ( ! g5]al pr9ciple1 b to ! error ( neglect+ to obs]ve ! limit+ conditions ( ! =mulation1 or ( neglect+ to make correspond+ corrections = ! non-obs]vance !re(4 ,summ>y4--,van 't ,h(f's !ory ( solution--t ! osmotic pressure ( sub/ances 9 solution obeys ! laws ( gases1 & t equal volumes ( ! mo/ v>i$ dilute solutions1 hav+ ! same temp]ature & osmotic pressure1 conta9 ! same numb] ( dissolv$ molecules1 t numb]1 namely1 :i* w\ld be f\nd 9 ! same volume ( a gas at ! same temp]ature & gas pressure1--accords ?us1 n only ) ! dem&s ( !rmodynamics1#bg b is also1 )9 ! limits dem&$ by ! !ory itself1 9 agreem5t ) ! be/ exp]im5tal measurem5ts ( osmotic pressures t h be5 made 9 rec5t ye>s4 ,! app>5t exceptions1 z 9 ! cases j describ$ &1 z we %all f9d1 9 ! case ( electrolytic dissociation1 are f\nd to be no exceptions1 :5 ! conclusions1 rea*$ on ! assumption t p#jbj ! !ory is correct1 are te/$ rigor\sly by indep5d5t me?ods ( inve/igation4#bh ,! fundam5tal laws ( gases & ! ,avogadro ,hypo!sis may be cond5s$ into ! foll[+ g5]al equation1 express+ all ( ! laws1 viz43 ,p ,v n ,r ,t4 ,?is equation applies equally to ! osmotic pressures ( dilute solutions1 ! osmotic pressure be+ sub/itut$ = ! gas pressure4 ,9 ! equation1 ,t is ! absolute temp]ature ( ! gas or solution1 ,p ! gase\s or osmotic pressure1 ,v ! free space ( ! gas volume1 i4e4 ! volume ( ! gas less ! volume occupi$ by ! gas molecules1 or ! volume ( ! pure solv5t 9 ! solution us$1 i4e4 ! volume ( ! solution less ! volume ( ! solute4 ,r is ! s-call$ gas-con/ant1 & repres5ts ! "w done aga9/ ! ext]nal pressure :5 "o gram molecule1 or mole1 ( ! gas is heat$ "o degree & all[$ to exp&1 say at con/ant pressure ,p1 aga9/ an ext]nal pressure ,p2 n repres5ts ! numb] ( gram molecules or moles ( gas or solute us$ 7! total weight ( solute or gas1 divid$ by ! av]age weight ( a mole 9 ! gas or solute74 ,if a giv5 weight ( a gas or solute is tak51 & no dissociation or association occurs 7su* z w\ld involve appreciable heats ( dilution71 !n n is a giv5 numb]2 &1 !re=e1 at a giv5 temp]ature ,t1 all ! factors on ! "r side ( ! g5]al equation be+ giv5 numb]s1 ,p ,v is a con/ant 7,boyle's law74 ,= a giv5 quantity ( gas or solute 7n is a giv5 numb]71 kept at con/ant volume ,v1 ! pressure mu/ v>y z ! absolute temp]ature 7,gay-,lussac's law72 ,p _/ ,t n ,r _/ ,v a con/ant4 ,:5 ! pressure1 volume & temp]ature ( two gases1 or two dilute solutions1 are equal1 n1 ! numb] ( gas or solute molecules pres5t1 mu/ be ! same 7,avogadro-van 't ,h(f ,hypo!sis72 n ,p ,v _/ 7,r ,t71 & all ! factors ( ! "r side are ! same = ! gases & solutions :i* we are comp>+4 ,f9ally1 if ! pressure is express$ 9 atmosph]es1 ! volume 9 litres1 & ! temp]ature 9 absolute degrees1 ! gas-con/ant ,r ,p ,v _/ ,t #a #bb4d _/ #bgc #j4jhb4 ,,footnotes3 #c ,ev5 aft] a solution ( uni=m conc5tration ( ! solute is =m$1 ! t5d5cy t[>d diffusion1 & ! diffusion itself1 & ! result+ pressure mu/ /ill p]si/4 ,b a /ate ( dynamic 7or fl[+7 equilibrium mu/ be consid]$ n[ to exi/1 ! loss caus$ by ! mov+ away ( ! solute1 f a giv5 "p ( ! solution1 be+ balanc$ by ! diffusion 7into t "p7 ( ! solute f ! neighbor+ p>ts4 ,:e!r "o ascribes ! diffusion to inh]5t molecul> velocities ( ! solute1 or to an attraction betwe5 solv5t & solute1 ! discrete p>ticles ( ! solute 9 a solution ( uni=m conc5tration w cont9ue to h su* inh]5t velocities 7,*ap4 ,,iii71 & w also cont9ue to be surr\nd$ by pure solv5t1 exactly z 9 solutions ( unequal conc5trations1 :]e ! diffusion may be obs]v$1 because ! net result1 9 su* a case1 is a "o-sid$ action4 #d ,?is aga9 holds equally = ! solv5t4 #e ,see bel[4 #f ,at ! same "t1 ! *ange is also 9 ! direction ( an expansion ( ! solv5t 9 ! solution4 ,! two *anges are n oppos$ to ea* o!r1 b supplem5t>y4 #g ,am4 ,*em4 ,j41 #bh1 #a 7#aijb72 #dj1 #bff1 #cbe 7#aijh7 7,/ud474 #h ,am4 ,*em4 ,j41 #cd1 #a 7#aije72 #cf1 #ci 7#aijf72 #cg1 #cbd1 #dbe1 #eeh 7#aijg72 #ch1 #age 7#aijg74 #i ,! exact conc5tration ( ! solution at ! po9t ( equilibrium is det]m9$ by subsequ5t analysis4 #aj ,cf4 ,smi?'s ,inorganic ,*emi/ry1 p4 #bhg4 #aa ,b]keley & ,h>tley1 ,phil4 ,trans4 ,roy4 ,soc4 ,a1 #bjf1 #dha 7#aijf74 #ab ,:5 appreciable heat ( dilution is %[n by a solution1 "s *emical *ange1 result+ f dilution1 is indicat$ 7su* z1 dissociation ( ! solute1 hydration1 hydrolysis1 etc474 ,9 su* a case1 ! ,avogadro-van 't ,h(f pr9ciple holds = ea* conc5tration = its actual composition1 & ! pr9ciple may (t5 be us$ to det]m9e ! ext5t ( ! *emical *ange produc$ by dilution4 ,b !n ! osmotic pressure w n obey ,boyle's & ,gay-,lussac's laws4 ,! same exception applies also to gases :i* und]go *emical *anges1 z ! result ( dilution or *ange ( temp]ature4 ,9 ! case1 = in/ance1 ( nitrog5 tetroxide1 :i* dissociates accord+ to ,n#b,o#d #b ,,no#b1 ! ext5t ( ! dissociation v>ies ) *anges ( conc5tration 7pressure7 & ( temp]ature1 & ! gas does n obey ! laws ( ,gay-,lussac & ( ,boyle4 ,9 reg>d to ! rle ( heat ( dilution 9 connection ) osmotic pressure1 see ,bancr(t1 ,j4 ,phys4 ,*em41 #aj1 #cai 7#aijf74 #ac ,see p4 #ae = a m rigor\s /atem5t conc]n+ ! volume4 ,cf4 ,morse & ,fraz]1 ,am4 ,*em4 ,j41 #cd1 #a 7#aije74 #ad ,z a result ( num]\s va9 endeavors1 z well z ( mu* direct evid5ce ( a positive "*1 ! sci5tific _w has1 = _m ye>s1 held ! op9ion t any sort ( p]petual motion ma*9e is impossible4 ,e "o n[ admits t a ma*9e :i* w\ld be able to "w cont9u\sly1 )\t consum+ en]gy1 is an impossibility--t is1 t a p]petuum mobile ( ! fir/ class1 z x is call$1 is impossible 7law ( ! cons]vation ( en]gy or fir/ law ( !rmodynamics74 ,f ?is law x does n ( necessity foll[1 h[ev]1 t x w\ld be impossible to make a ma*9e or device t w\ld conv]t cont9u\sly into available en]gy or "w1 say1 ! enorm\s am\nts ( heat en]gy ( ! e>? or ( l>ge bodies ( wat] 7dissipat$ en]gy7 :i* w\ld !reby be cool$ bel[ ! temp]atures ( _! surr\nd+s4 ,su* a hypo!tical process has be5 t]m$ a p]petuum mobile ( ! second class2 x has nev] be5 realiz$ & is univ]sally conc$$ to be an impossibility2 ! s-call$ second law ( !rmodynamics gives expression to ?is fact4 ,n[ van 't ,h(f ,z4 phys4 ,*em41 #a1 #dha 7#ahhg7 %[$1 fir/1 t a gas l oxyg51 nitrog51 hydrog51 etc41 :i* is soluble 9 proportion to its gas pressure 7,h5ry's law71 mu/ ex]t1 9 solution1 an osmotic pressure equal to ! gas pressure1 :i* x w\ld h1 if pres5t 9 ! same quantity z a gas 9 ! same volume at ! same temp]ature2 =1 if su* 7 n ! case1 ! solution & gas c\ld be us$ to produce a p]petuum mobile ( ! second class1 :i*1 accord+ to ! above law1 is an impossibility4 ,simil> pro(s 7 giv5 by ,rayleigh ,nature1 #ee1 #bec 7#ahig7 & by ,l>mor ,phil4 ,trans41 #aij1 #bff 7#ahig71 ,nature1 #ee1 #ede 7#ahig7 t ! pr9ciple applies to solutions ( o!r solutes4 ,provid$1 !n1 t we h 7#a7 p]fect semip]meable membranes1 7#b7 suffici5tly dilute solutions1 & 7#c7 none b negligible heats ( dilution 7p4 #ab71 van 't ,h(f's g5]alization1 conc]n+ ! relation ( osmotic pressure & ! laws ( gases1 mu/ hold1 if ! p]petuum mobile ( ! second class is impossible1 z is dem&$ by ! second law ( !rmodynamics4 #ae ,see p4 #ae 9 reg>d to ! relation = conc5trat$ solutions4 #af ,! pressure ,p#j ( a giv5 quantity 7weight7 ( a gas at #j ,c41 9 a giv5 con/ant volume1 is also a giv5 numb] & consequ5tly ,p#j_/bgc is a con/ant "u ^! conditions4 #ag ,! slight diff]5ces 9 ! ionization ( copp] sulphate solutions ( #ad & #ag & at #bj & #hj are n includ$ 9 ! calculation1 ionization be+ unkn[n1 :5 van 't ,h(f made 8 calculations4 #ah ,am4 ,*em4 ,j41 #da1 #beh 7#aiji74 #ai ,9 ! light ( rec5t "w1 especially by ,morse & ,fraz]1 ! law w\ld /ate1 m exactly1 t a sub/ance 9 solution produces ! osmotic pressure1 at a giv5 temp]ature1 :i* x w\ld ex]t1 if x 7 conta9$ z a gas1 at ! same temp]ature1 9 ! volume occupi$ by ! pure solv5t ( ! solution4 ,= suffici5tly dilute solutions1 ! volume ( ! solution & ! volume ( ! solv5t may be consid]$ id5tical2 = m conc5trat$ solutions1 !re is a decid$ diff]5ce1 & ! correct volume to use 9 calculation is ! volume ( ! solv5t alone1 i4e4 ! volume ( ! solution r$uc$ by ! volume ( ! pure solute4 ,?is corresponds to ! correction ( ! volume 9 ! m accurate expression = ! behavior ( gases1 develop$ by van d] ,waals2 9 place ( v1 ! total gas volume1 7v b71 ! total volume ( ! gas less ! volume ( ! sph]es ( action ( ! gas p>ticles1 is us$1 especially = /rongly compress$ or conc5trat$ gases4 ,x may be add$ t van 't ,h(f's !rmodynamic pro( involves ! same correct def9ition ( ! volume t ,morse & ,fraz] subsequ5tly develop$ exp]im5tally4 ,cf4 ,bancr(t1 ,j4 ,phys4 ,*em41 #aj1 #cai 7#aijf74 #bj ,"o gram ( cane sug>1 ,c#ab;,h#bb,o#aa 7! mol4 wt4 is #cdb7 corresponds to #a _/ #cdb gram molecule or mole &1 !re=e1 to #b4jb _/ #cdb gram ( hydrog54 ,! volume conta9+ ?is quantity ( hydrog5 is #ajj4f c4c42 a lit] w\ld conta9 #b4jb _/ #cdb #ajjj _/ #ajj4f gram ( hydrog54 ,! pressure ( a mole or #b4jb grams ( hydrog51 conta9$ 9 a lit] at #j1 is #bb4d atmosph]es1 & ! pressure ( ! quantity ( hydrog5 giv5 above1 9 a lit]1 w\ld be 7#b4jb #ajjj7 _/ 7#cdb #ajj4f7 7#bb4d _/ #b4jb7 at #j4 ,at #cf ,c41 = in/ance1 ! pressure w\ld be #cji _/ #bgc times z great1 or ,pcalculat$ 7#b4jb #ajjj #bb4d #cji7 _/ 7#cdb #ajj4f #b4jb #bgc7 #j4gce atmosph]e4 #ba ,! exact relations are discuss$ 9 van 't ,h(f's ,lectures on ,physical ,*emi/ry1 ,"p ,,ii1 pp4 #db-ei1 ,n]n/'s ,!oretical ,*emi/ry 7#aijd71 pp4 #adb & #adh1 & ,h4 ,c4 ,jones's ,! ,elem5ts ( ,physical ,*emi/ry 7#aiji71 pp4 #beb1 #bga4 #bb ,vide ,ra\lt1 ,sci5tific ,memoir ,s]ies1 #d1 #ga1 #abg4 #bc ,i4e4 abnormally small depressions ( freez+-po9ts or elevations ( boil+-po9ts4 #bd ,n]n/1 ,!oretical ,*emi/ry1 p4 #dhf2 ,h5drixson1 ,z4 anorg4 ,*em41 #ac1 #gc 7#ahig74 #be ,cf4 ,bancr(t1 ,j4 ,phys4 ,*em41 #aj1 #cai 7#aijf74 #bf ,= ! discussion ( o!r in/ances1 vide ,bancr(t1 loc4 cit4 #bg ,footnote #c1 p4 #ab4 #bh ,= example1 det]m9ations ( di/ribution coeffici5ts 7p4 #ah71 heats ( dilution 7p4 #ai71 conductivities & *emical activity 7,*apt]s ,,iv-,,vi74 p#jba ,,*apt] ,,iii ,,osmotic ,,pressure ,,& ,,! ,,!ory ,,( ,,solution ,,ii ,accept+ van 't ,h(f's !ory ( solutions1 !n1 z bas$ on exp]im5tal evid5ce z well z on s\nd !rmodynamic reason+1 we f9d a numb] ( int]e/+ que/ions /ill confront+ u4 ,mo/ insi/5t is ! "q z to ! s\rce ( ! rem>kable agreem5t betwe5 ! osmotic pressure ( a solute & ! gas pressure1 :i* x w\ld ex]t 9 ! same volume1 z a gas1 at ! same temp]ature1 & z to ! id5tity ( ! laws gov]n+ ! two =ms ( pressure4 ,!n1 we may also ask1 :at is ! me*anism ( ! process by :i* osmotic pressure reveals itself1 especially 9 ! case ( cells ) semip]meable membranes4 ,&1 f9ally1 we may ask :at is ! cause ( ! semip]meability ( ! membranes4 ,semip]meability4--,tak+ up ! la/ "q fir/1 z ! simple/ "o1 we f9d t x 0 long ago recogniz$ t p]meability dep5ds on ! p[] ( membranes to dissolve c]ta9 sub/ances1 or to =m un/able comb9ations ) !m4 ,a membrane is semip]meable if x w dissolve "o compon5t only ( a solution1 ! solute or ! solv5t1 & n ! o!r4#bi ,we f9d ! simple/ evid5ce ( ! cause ( semip]meability 9 ! case ( gases4 ,palladium1 especially :5 heat$1 dissolves hydrog5 readily1 b n nitrog5 or oxyg51 & a wall ( palladium may be us$ z a semip]meable membrane to sep>ate a mixture ( hydrog5 & nitrog5 f pure hydrog51 j z copp] f]rocyanide membranes are us$ ) aque\s sug> solutions & wat]4 ,! results ) ! gases duplicate 9 e p>ticul> ! obs]vations made on ! solutions 7see bel[1 p4 #bd74 ,c]ta9 gases1 su* z ammonia & hydrog5 *loride1 are easily soluble 9 wat]1 :ile o!rs1 l oxyg51 nitrog5 & hydrog51 are v difficultly soluble1 & a film ( p#jbb wat] may be us$ z a semip]meable membrane = su* gases4#cj ,,exp4 ,if ! moi/ membrane ( a cell 7,fig4 #d71 conta9+ air1 is cov]$ ) an atmosph]e ( hydrog51 !re is no increase ( pressure produc$ 9 ! cell1 z indicat$ by ! column ( color$ oil 9 ! manomet] 9 :i* ! cell ends3 hydrog51 be+ v little soluble 9 wat]1 _c pass ?r\gh ! film ( wat] 9 ! few m9utes x is all[$ to act4 ,if n[ an atmosph]e ( ammonia is sub/itut$ = ! hydrog51 ! gas passes ?r\gh ! film into ! cell4 ,x turns ! color ( a piece ( litmus pap] plac$ 9 ! cell & produces an increas$ pressure 9 ! cell1 ! air rema9+ 9 ! latt]1 because oxyg5 & nitrog5 are v little soluble 9 wat]4 ,illu/ration3 ,,fig4 #d4 ,membranes w be1 simil>ly1 semip]meable to solv5t or solute1 :5 only "o ( ^! is soluble 9 ! membrane1 or is capable ( =m+ an un/able comp\nd ) x4 ,= in/ance1 salts1 hold+ wat] ( cry/allization :i* is readily lo/ & recov]$1 may easily be conceiv$ ( z assum+ ! rle ( semip]meable membranes1 all[+ ! passage ( wat] say f a wet atmosph]e to a dry "o1 or f pure wat] to a solution2 & ,tammann#ca has realiz$ su* membranes by ! use ( zeolites--silicates1 :i* hold wat] ( cry/allization b are insoluble 9 wat]4 ,kahl5b]g#cb has rec5tly us$ rubb] membranes1 t are p]meable = solv5ts l b5z5e1 pyrid9e1 etc41 :i* are soluble 9 rubb]1 b n p]meable = wat]1 :i* is insoluble 9 rubb]4 ,illu/ration3 ,,fig4 #e4 ,osmosis4--,! recognition ( ?is rle ( ! semip]meable membrane leads to ! second "q rais$1 namely z to ! me*anism ( ! process by means ( :i* osmotic pressures are measur$ directly ) ! aid ( su* membranes 7p4 #aa74 p#jbc ,! answ] h+es on ! "q ( ! me*anism ( ! diffusion ( ! solv5t into ! cell1 a diffusion :i* is call$ its osmosis4#cc ,if we consid] ! pure solv5t1 say wat]1 on "o side ( a semip]meable membrane1 & a solution 7e4g4 ( sug> 9 wat]7 on ! o!r side1 x is obvi\s t ! solv5t itself has a high] conc5tration on ! side :]e x is pure1 ?an on ! side ( ! solution1 :]e x is dilut$--di/5d$ by ! solute 9 x4 ,! solv5t is soluble 9 ! membrane1 & its solubility w be proportional#cd to its own 7! solv5t's7 conc5tration2 x w1 consequ5tly1 be m soluble 9 ! membrane on ! side ( ! pure solv5t ?an on ! side ( ! solution4 ,if we br+ su* a membrane fir/ into contact ) ! pure solv5t 7,fig4 #e71 ! membrane w take up ! solv5t 7f ! side ,a7 until x is saturat$ ) x4 ,let ! solubility1 :i* repres5ts ! conc5tration ( ! solv5t 9 ! membrane at ?is /age1 be call$ c4 ,! membrane may !n be consid]$ to be tak+ up 9 unit "t j z _m molecules f ! solv5t z x gives up to x 7dynamic equilibrium71 exactly z1 :5 wat] is 9 equilibrium ) wat] vapor1 we consid] ! wat] to be vaporiz+ j z fa/ z vapor is cond5s+ to =m wat]4 ,n[1 if a solution ( sug> is plac$ on ! o!r side ( ! membrane1 ! solv5t w pass out ( ! membrane into ! solution j z fa/ z x passes back into ! pure solv5t4 ,at fir/ ! conc5tration ( ! solv5t on ! surface ,b ( ! membrane is j z great 7c7 z on ! surface ,a2 b ! membrane w "h receive ! solv5t m sl[ly f ! solution1 :i* is less conc5trat$ z to ! solv5t2 & consequ5tly ! membrane w lose wat] to ! solution4 ,! solubility 7c7 ( ! solv5t at ?is surface ,b ( ! membrane1 correspond+ to ! small] conc5tration ( ! solv5t 9 ! solution1 w be less ?an ! solubility 7c7 at ,a1 :]e ! membrane is 9 contact ) ! pure solv5t1 & wat] w pass into ! solution at ,b1 until ! conc5tration ( ! wat] 9 ! membrane at ,b has fall5 p#jbd f 7c7 to 7c74 ,9 su* a membrane1 z 9 e solution or gas1 !re mu/ be a t5d5cy t[>ds ! e/abli%+ ( uni=m conc5tration by diffusion f po9ts ( high] conc5tration to ^? ( l[]1 & ! solv5t w1 !re=e1 diffuse f po9ts along ! surface ,a ( ! membrane to po9ts along ! surface ,b2 ! surface ,a w become unsaturat$ & w take up solv5t f ! pure liquid ba?+ x1 & ! surface ,b w be kept cont9u\sly sup]saturat$ & w lose solv5t cont9ually to ! solution4 ,consequ5tly1 ! solv5t w pass cont9u\sly ?r\gh ! membrane f ! pure solv5t to ! solution4 ,equilibrium w be rea*$1 & ! fl[ w cease1 only :5 ! solution has become inf9itely dilute1 equal hydro/atic pressure obta9+ on solution & solv5t1 or :5 ! di/urb+ influ5ce ( ! solute1 :i* dilutes ! solv5t 9 ! solution1 is exactly c\nt]balanc$ by an ext]nal hydro/atic pressure1 ex]t$ on ! solution4 ,:5 su* a pressure on ! surface ( ! solution balances ! =ce ex]t$ aga9/ ! solv5t by ! solute we %all h equilibrium4 ,x is cle>1 !n1 t ! osmosis1 or passage ( ! solv5t ?r\gh ! membrane1 is br\ght ab\t by ! unequal conc5trations 7or1 m exactly1 ! result+ unequal p>tial pressures7 ( ! solv5t itself4 ,b ?is inequality is produc$ by ! pres5ce ( ! solute1 & x is a *>act]i/ic & significant fact1 t ! effect ( ! latt]1 9 dilute solutions1 may be ov]come by a hydro/atic pressure1 correspond+ to ! gas pressure :i* ! same numb] ( molecules ( a gas 9 ! same volume at ! same temp]ature w\ld ex]t aga9/ ?is hydro/atic pressure4 ,illu/ration3 ,,fig4 #f4 ,osmosis & ,gas ,pressure4--,! legitimacy ( ! int]pretation giv5 is mo/ /rik+ly %[n by exp]im5ts ) a membrane1 semip]meable = gases1 :i* enables u to measure gas pressures1 t may be unkn[n1 by exactly ! same process z is us$ to measure ! unkn[n osmotic pressure ( a solute 9 solution4 ,van 't ,h(f#ce & ,arrh5ius#cf pr$ict$ su* a result1 & ,ramsay#cg prov$ by exp]im5t ! correctness ( _! assumptions4 ,a mixture ( nitrog5 & hydrog5 may be enclos$ 9 a palladium vessel connect$ ) a manomet] 7see ,fig4 #f74ch ,! p>tial pressure ,p,n ( ! nitrog5 may be p#jbe det]m9$ by surr\nd+ ! palladium vessel ) pure hydrog51 at a pressure :i* is kn[n & is great] ?an ! p>tial pressure ( ! hydrog5 9 ! vessel1 & by obs]v+ ! f9al total gas pressure :i* is obta9$ 9 ! vessel4 ,! hydrog5 diffuses f ! po9t ( high] conc5tration1 outside ( ! vessel1 ?r\gh ! palladium1 into ! int]ior :]e ! conc5tration ( ! hydrog5 is l[]4 ,! exp]im5t may be c>ri$ out at #bhj1 a temp]ature at :i* palladium readily dissolves hydrog5 & is p]meable to x4 ,! metal does n dissolve nitrog5 & is n p]meable to x4 ,! volume ( ! enclos$ gas is kept con/ant by rais+ ! m]cury level 9 ! outside arm ( ! manomet]1 & ! total pressure ( ! enclos$ gas is measur$ :5 equilibrium is rea*$4 ,if ?is total pressure is ,pf9al & ! kn[n pressure ( ! hydrog5 outside ( ! vessel is ,p,h1 !n1 if equilibrium is rea*$ :5 ! hydrog5 on bo? sides ( ! semip]meable palladium membrane has ! same conc5tration 7pressure71 ,p,h ,p,n ,pf9al & ,p,n ,pf9al ,p,h4 ,9 o!r words1 ! excess ( ! f9al comb9$ pressure inside1 ov] ! outside pressure ( ! hydrog51 is equal to ! pressure ( ! nitrog5 9 ! vessel4 ,ramsay's results %[$ t ! am\nt ( hydrog5 actually ent]+ ! vessel 0 #ij-ig ( ! am\nt pr$ict$ by ! !ory on ! basis ( ! assumption t equilibrium w be rea*$1 :5 ! hydrog5 has ! same conc5tration 7pressure7 on bo? sides ( ! palladium membrane4 ,! exp]im5t is p>ticul>ly in/ructive1 9 ! fir/ place1 because x illu/rates ) a gas1 subject to ! laws ( gases1 :y & h[ osmosis takes place ?r\gh a semip]meable membrane--namely z a result ( ! solubility ( ! diffus+ sub/ance 9 ! membrane1 & ?r\gh ! fl[ ( ! diffus+ sub/ance p#jbf f high] to l[] conc5trations4 ,9 ! second place1 :ile ! increase 9 total pressure 9 ! inn] *amb] und\bt$ly is br\ght ab\t by ! osmosis ( hydrog5 into ! *amb]1 ! excess pressure :5 equilibrium has be5 rea*$1 necess>ily measures accurately ! p>tial pressure ( ! nitrog54 ,9 o!r words1 ! semip]meable membrane is m]ely a means or device = measur+ ! p>tial pressure ( ! nitrog5--! membrane is n ! cause ( ! pressure2 ! latt] is a def9ite "o1 :e!r we "k :at x is or n1 & ! osmosis ( ! hydrog5 ?r\gh ! palladium m]ely gives u a means ( asc]ta9+ x4 ,simil>ly1 x w\ld be wrong to consid] t ! osmotic pressure ( a solution is caus$1 or br\ght ab\t1 by ! fl[ ( ! solv5t ?r\gh a semip]meable membrane 7osmosis72 ! latt] simply is a device :i* enables u to recognize & measure ! pressure t exi/s 9 ! solution1 bo? 9 ! pres5ce & ! abs5ce ( su* a membrane4 ,we may consid]1 !n1 t ! osmosis1 or migration ( ! solv5t ?r\gh a semip]meable membrane into a solution1 is ! result ( ! r$uc$ conc5tration 7or p>tial pressure7 ( ! solv5t 9 ! solution1 result+ f ! pres5ce ( ! solute4 ,inasmu* z ! effect ( ! solute on ! solv5t c be ov]come by a pressure on ! surface ( ! solution1 "o is l$ to ! conclusion t ! solute acts by ex]t+1 9 turn1 a =ce or pressure aga9/ ! surfaces ( ! solv5t1 9 ! directions opposite to ! hydro/atic pressure requir$ to ov]come x4 ,! significant id5tity ( ! value ( ?is pressure1 z ?us measur$1 ) ! gas pressure t w\ld be ex]t$ by a gas ( ! same numb] ( molecules1 9 ! same volume & at ! same temp]ature1 leads u to ! la/ ( ! ?ree que/ions :i* h be5 rais$1 namely1 ! "q conc]n+ ! !ory ( ! intimate relations betwe5 gas & osmotic pressures 7p4 #ba74 ,! ,k9etic ,!ory & ,osmotic ,pressure4--,= an answ] to ?is fundam5tally int]e/+ !oretical "q "o turns1 naturally1 to ! k9etic !ory1 :i*1 9 ! h&s ( ,clausius1 ,j\le1 van d] ,waals & o!rs1 has giv5 u a v satisfactory & ess5tially complete !oretical int]pretation ( ! behavior ( gases1 & ( ! liquids to :i* !y may be compress$4 ,! laws ( gases1 x is kn[n1 are 9 accord ) ! two simple assumptions ( ! k9etic !ory4 ,! fir/ assumption is t p#jbg gases consi/ ( ultimate discrete p>ticles 7molecules71 :i* move 9 all directions ?r\gh ! space fill$ by ! gas &1 at ord9>y pressures1 are s f> ap>t1 t ! =ces ( molecul> attraction betwe5 !m are negligible2 ! pressure ( ! gas is simply ! net result ( ! impacts ( ^! fly+ p>ticles ^u ! walls ( ! conta9+ vessel4 ,! second assumption ( ! k9etic !ory is t temp]ature is a function ( ! mean k9etic en]gy ( ! mov+ molecules1 & t ! molecules ( gases ( ! same temp]ature h ! same mean k9etic en]gy4 ,! k9etic en]gy ( p>ticles is a function ( _! mass m & _! velocity u 7,k4,e4 m u#b74 ,:5 a gas is heat$1 ! k9etic en]gy ( its molecules is increas$1 &1 s9ce _! masses rema9 un*ang$1 _! velocity mu/ increase4 ,z a result1 ! numb] & ! =ce ( _! impacts aga9/ ! walls ( a giv5 space increase1 & ?us ! pressure is increas$4 ,we may ask1 :e!r ?is !ory _c be us$ to expla9 ! connection betwe5 osmotic & gase\s pressure4 ,if temp]ature is a function ( ! k9etic en]gy ( ! molecules ( :i* a sub/ance consi/s1--& ! :ole behavior ( gases confirms su* a conception1--!n "o mu/ conclude1 t ! mean k9etic en]gy ( molecules1 at a giv5 temp]ature1 mu/ always be ! same1 irrespective ( :e!r !y are pres5t 9 gase\s1 or liquid1 or solid =m1 or ev5 9 solution4#ci ,! t5d5cy ( ! molecules to move1 result+ f ! k9etic en]gy inh]5t at a giv5 temp]ature1 may be l>gely balanc$ 7liquids71 or ov]come 7solids71 by molecul> attractions ( surr\nd+ p>ticles1 b su* conditions are altoge!r 9 h>mony ) ! conception ( a def9ite mean molecul> k9etic en]gy1 p]si/+ at a giv5 temp]ature1 irrespective ( ! physical surr\nd+s ( ! molecule4 ,accord+ to ! k9etic !ory1 !n1 :5 we h a dilute solution1 say ( alcohol 9 wat]1 ! molecules ( alcohol1 at a giv5 temp]ature1 w\ld h a giv5 mean k9etic en]gy1 p#jbh & w\ld be t5d+ to move 9 all directions ) a mass#dj & velocity1 ! same z if ! alcohol 7 pres5t z a gas or vapor at ! same temp]ature4 ,if ! solution is suffici5tly dilute1 ! dissolv$ alcohol molecules are suffici5tly f> ap>t1 = av]age "t1 to make ! molecul> attractions betwe5 !m negligible1 j z is assum$ = gases4 ,z f> z ! alcohol 7solute7 molecules alone are conc]n$1 !y may1 evid5tly1 be assum$ to be pres5t 9 ! solution1 9 ! same condition1 z to numb]1 mean k9etic en]gy & mean velocity1 z !y w\ld be 9 alcohol vapor ( ! same conc5tration & temp]ature4 ,we may ask1 n[1 :e!r ! osmotic pressure ( ! solution may n result f ! pressure on ! solv5t1 gr[+ out ( its bomb>dm5t by ! solute molecules4 ,& we may ask1 fur!r1 :at num]ical relation w\ld subsi/ betwe5 su* a pressure & ! pressure ( ! solute1 if ! latt] 7 pres5t z a gas1 "u ! same conditions ( temp]ature & conc5tration4 ,9 ord] to be prep>$ to answ] ^! que/ions1 we mu/ consid]1 9 :at way ! pres5ce ( ! solv5t mu/ modify ! motions & ! =ces ( impact ( solute molecules4 ,"o great diff]5ce betwe5 ! dissolv$ sub/ance & ! gas w\ld be1 t1 9 ! solution1 ! solute is 9 intimate contact ) ! solv5t4 ,a decid$ attraction mu/ exi/ betwe5 ! solute molecules & ! solv5t molecules1 s9ce we c\ld n o!rwise und]/& h[ a solv5t1 l wat]1 9 dissolv+ a nonvolatile sub/ance l sug>1 c\ld ov]come ^? molecul> attractions betwe5 ! sug> molecules1 :i* make sug> a solid4 ,b we note1 t all ! solute molecules 9 a solution1 except ^? at ! surface1 are surr\nd$ on all sides equally by ! solv5t4 ,! attractive =ces1 ex]t$ ^u ! s+le molecules ( ! solute by ! solv5t molecules1 ?us sum up to z]o1 & ne$ n be consid]$ fur!r4 ,only ! small numb] ( solute molecules1 :i* are at ! surface ( ! liquid1 w\ld involve a m9or correction 9 ! application ( ! k9etic !ory1 & ?is ne$ n be consid]$ "h4 ,a second po9t ( diff]5ce betwe5 a sub/ance 9 solution1 & ! same sub/ance z a gas or vapor at ! same temp]ature p#jbi 9 ! same volume1 lies 9 ! fact t a gas molecule w g a mu* great] di/ance )\t collid+ ) "s second molecule & *ang+ its pa?1 ?an w\ld a solute molecule1 ! latt] molecule be+ closely surr\nd$ by ! molecules ( ! solv5t4 ,! mean free pa?1 z x is call$1 w be v mu* %ort] = a solute molecule ?an = a gas molecule1 & we note1 z a matt] ( fact1 h[ sl[ is ! diffusion ?r\gh a solv5t 7see exp4 p4 #h74 ,b ! %ortness ( ! previ\s pa? does n affect ! =ce ( a bl[ result+ f ! impact ( a mov+ mass1 ! =ce ( ! impact be+ dep5d5t only on ! mass & ! *ange 9 spe$ ( ! /rik+ p>ticle1 at ! mom5t ( impact4 ,?us ! %ort free mean pa? ( a dissolv$ molecule does n affect ! mean =ce ( ! bl[1 deliv]$ :5 x /rikes ! resi/+ m$ium4 ,! sl[ diffusion ( a dissolv$ sub/ance repres5ts a diff]5ce 9 degree1 n 9 k9d1 betwe5 gases & dissolv$ sub/ances4 ,ev5 9 gases1 we h su* frequ5t collisions t ! mean free pa? ( an oxyg5 molecule at #j & atmosph]ic pressure is only #j4jjjja cm41 :]eas ! velocity1 ! total pa? cov]$ 9 "o second1 is #db1ejj cm4 ,,exp4 ,if a bulb conta9+ a few drops ( brom9e is brok5 at ! bottom ( a tall cyl9d]1 ! brom9e vapor is se5 to diffuse r sl[ly into ! upp] "p ( ! cyl9d]1 ! brom9e molecules1 9 _! passage upw>d1 reb\nd+ f ! air molecules1 ) :i* ! cyl9d] is fill$4 ,if a second cyl9d] is fir/ evacuat$1 & ! brom9e bulb is brok5 9 vacuo1 ! vapor is se5 to fill ! cyl9d] in/antly1 ! high velocity ( ! brom9e molecules be+ ?us reveal$4 ,b a ?ird "q1 ( fundam5tal importance 9 ! comp>ison ( ! condition ( a sub/ance exi/+ z a gas & its condition 9 a solution ( ! same conc5tration & temp]ature1 results f a consid]ation ( ! frequ5cy ( ! impacts ( ! solute molecules aga9/ ! solv5t1 gr[+ out ( ! r$uction ( ! l5g?s ( ! mean free pa?s ( ! solute molecules4#da ,9 ord] to be able to take ?is fact prop]ly into acc\nt1 x w be necess>y to consid] some:at m precisely ! mann] 9 :i*1 accord+ to ! k9etic !ory1 gas pressure is produc$4 ,we may consid] t we h 9 a cube ( unit volume 7#a c4c47 n molecules ( a gas1 ea* ( mass m & av]age velocity u cm4 p] second4 ,we may assume t "o-?ird ( ! total numb] p#jcj ( molecules moves 9 ea* ( ! ?ree dim5sional directions4#db ,a s+le molecule ( mass m1 /rik+ ! surface ) a velocity u & reb\nd+ ) ! same velocity 9 ! opposite direction1 w ex]t on ! surface a =ce ( #b m u units4 ,b1 ) a velocity ( u cm4 p] second1 x w rea* ! opposite wall & return to ! surface we are consid]+1 u _/ #b times 9 "o second4 ,a s+le molecule w consequ5tly ex]t a =ce #b m u u _/ #b or m u#b on ! surface1 & ! n _/ #c molecules mov+ 9 ! same direction w ex]t a =ce n _/ #c m u#b on ! unit surface4 ,?is repres5ts1 !re=e1 ! pressure ( su* a gas1 z calculat$ on ! basis ( ! assumptions ( ! k9etic !ory4 ,n[1 :5 a gas is s /rongly compress$1 t ! bulk ( ! molecules is n negligible 9 comp>ison ) ! total volume ( ! gas1 ! numb] ( impacts on unit surface 9 unit "t becomes s5sibly great] ?an n _/ #c u _/ #b1 s9ce ! di/ance to be cov]$ betwe5 successive bl[s on ! surface w be s5sibly less ?an #b cm41 9 a cube ( unit volume4 ,if we imag9e1 = ! sake ( a r\gh illu/ration1 t "o-?ird ( ! molecules 9 #a c4c4 are unit$ into "o sph]ical mass 7indicat$ by ,a 9 ,fig4 #g71 mov+ upw>ds & d[nw>ds1 x is obvi\s t ! di/ance cov]$ betwe5 two successive bl[s on a surface is n #b cm41 b t di/ance dim9i%$ by twice ! diamet] ( ! sph]e4 ,= /rongly compress$ gases1 ! total numb] ( impacts on unit surface is !re=e s5sibly great] ?an n _/ #c u _/ #b1 & ! pressure is proportionately great]4 ,accord+ to van d] ,waal's correction = ?is effect1 ,p n _/ #c m u#b _/ 7#a b71 :]e b repres5ts ! volume actually occupi$ by ! molecules 9 #a c4c4 ( ! gas4#dc ,illu/ration3 ,,fig4 #g4 ,n[1 = solute molecules1 ! free space ( movem5t1 z we may call x1 is1 simil>ly1 v consid]ably r$uc$ by ! pres5ce p#jca ( ! solv5t1 & ! r$uction ( ?is free space1 z ,n]n/ has %[n1 w h ! same effect on ! pressure produc$ aga9/ unit surface ( ! solv5t by ! bomb>dm5t ( ! solv5t by ! solute1 z ! r$uction ( ! free space has on ! gas pressure :5 a gas is /rongly compress$4 ,! result+ pressure on unit surface ( ! solution mu/ ?us be increas$1 f ! pressure ,pgas1 :i* w\ld be ex]t$ by ! solute aga9/ ! walls ( a vessel1 if x 7 pres5t z a gas ( ! same conc5tration1 at ! same temp]ature1 to ,pgas _/ 7#a v71 :]e v repres5ts ! real volume occupi$ by ! solv5t & 7#a v7 ! free space = ! solute molecules 9 unit volume ( solution4#dd ,if osmotic pressure is ! result ( su* a bomb>dm5t ( ! solv5t by ! molecules ( ! solute1 "o might1 !re=e1 expect to f9d ! osmotic pressure v mu* great] ?an ! gas pressure ( ! same sub/ance 9 ! same volume at ! same temp]ature4 ,h[ev]1 9 all ! exp]im5tal det]m9ations 7by means ( semip]meable membrane1 vapor pressure1 boil+-po9t & freez+-po9t measurem5ts7 ( ! osmotic pressure z def9$ on p4 #aj1 ?is corrective factor cancels out aga94#de ,accord+ to ! k9etic !ory1 ! osmotic pressure ( a sub/ance 9 dilute solution %\ld1 consequ5tly1 be f\nd by exp]im5t to be equal to ! gas pressure :i* a gas1 ( ! same molecul> conc5tration1 w\ld ex]t at ! same temp]ature4#df ,we f9d ?us t ! significant co9cid5ce betwe5 ! osmotic pressure ( a sub/ance 9 dilute solution1 z def9$ & measur$ accord+ to van 't ,h(f1 & ! gas pressure :i* ! sub/ance w\ld ex]t1 if x 7 pres5t z a gas 9 ! same volume & at ! same temp]ature1 is 9 agreem5t ) ! fundam5tal assumptions ( ! k9etic !ory4 ,?is !ory1 consequ5tly1 gives u an adequate !oretical explanation ( p#jcb osmotic pressure1 z x does ( gas pressure4 ,z van 't ,h(f says1#dg if ! osmotic pressure foll[s ,gay-,lussac's law & is proportional to ! absolute temp]ature1 !n1 l gas pressure1 x w become z]o at #j absolute temp]ature & w vani% :5 molecul> movem5ts come to re/4 ,x is !re=e natural to look = ! cause ( osmotic pressure 9 k9etic ph5om5a & n 9 attractions4#dh ,,footnotes3 #bi ,l',h]mite1 ,compt4 r5d41 #ci1 #aagg 7#ahed72 van 't ,h(f1 ,lectures on ,physical ,*emi/ry1 ,"p ,,ii1 p4 #cg4 #cj ,n]n/1 ,!oretical ,*emi/ry1 p4 #ajc4 #ca ,van 't ,h(f1 ,lectures on ,physical ,*emi/ry1 ,"p ,,ii1 p4 #cg4 #cb ,j4 ,phys4 ,*em41 #aj1 #ada 7#aijf74 #cc ,?is t]m mu/ n be conf\nd$ ) ! t]m osmotic pressure1 :i* has be5 def9$ on p4 #aj4 #cd ,see ,*apt] ,,vii on ! law ( physical or het]og5e\s equilibrium1 :]e ! relations are discuss$ 9 detail4 #ce ,z4 phys4 ,*em41 #e1 #age 7#ahij74 #cf ,ibid41 #c1 #aai 7#ahhi74 #cg ,phil4 ,mag41 #ch1 #bjf 7#ahid74 #ch ,cf4 van 't ,h(f's ,lectures on ,physical ,*emi/ry1 ,vol4 ,,ii1 #dj 7#ahii74 #ci ,! molecules may h diff]5t masses 9 ! diff]5t conditions1 & ! pr9ciple ( ! mean k9etic en]gy w\ld always apply to !m z !y are1 9 ! condition "u obs]vation1 & n z !y are 9 "s o!r condition2 any *ange 9 mass1 9 solution1 = in/ance1 w\ld %[ itself 9 ! osmotic pressure measurem5ts 7see p4 #ah71 j z x is %[n 9 ! measurem5ts ( gases1 :5 ! gas molecules %[ a *ange 9 composition1 z is ! case ) hydrog5 fluoride 7,h#b;,f#b #b ,,hf71 nitrog5 tetroxide 7,n#b,o#d #b ,,no#b71 phosphorus p5ta*loride 7,p,cl#e ,p,cl#c ,cl#b7 & o!r comp\nds4 #dj ,! molecul> weight ( alcohol 9 dilute aque\s solution is ! same 7#df7 z 9 vapor =m4 ,ra\lt1 ,z4 phys4 ,*em41 #bg1 #fef2 ,loomis1 ibid41 #cb1 #eib4 #da ,n]n/1 ,!oretical ,*emi/ry1 p4 #bde4 #db ,?is assumption is n made 9 ! rigor\s developm5t ( ! above relations on ! basis ( ! k9etic !ory1 b x leads to ! same net result4 #dc ,ev5 = gases ( ord9>y conc5tration1 ! introduction ( ! same correction gives an expression = ! relation ( pressure & volume1 :i* is m exact ?an ,boyle's law & is us$ 9 all exact calculations ) gases4 #dd ,"o may imag9e1 fir/1 n molecules ( ! solute z a gas1 ) ! pressure ,pgas1 9 #a c4c4 ,!n1 "o may imag9e1 crudely1 ! n molecules ( solute1 9 a free 7gas7 space ( 7#a v7 c4c41 9 ! c5t] ( #a c4c4 ( ! solv5t1 & ex]t+ by _! impacts a pressure ,posm41 aga9/ ! solv5t4 ,accord+ to ,boyle's law1 we %\ld !n h1 ,pgas #a ,posm4 7#a v71 & !re=e ,posm4 ,pgas _/ 7#a v74 #de ,vide ,n]n/1 ,!oretical ,*emi/ry1 p4 #bde1 = ! detail$ discussion ( ?is relation4 #df ,?is conclusion is rea*$ m rigor\sly & m simply by !rmodynamic analysis4 #dg ,lectures on ,physical ,*emi/ry1 ,"p ,,ii1 p4 #ce4 #dh ,rigor\s developm5ts ( ! relations betwe5 solute & solv5t1 = dilute & conc5trat$ solutions1 h be5 made by van d] ,waals1 ,z4 phys4 ,*em41 #e1 #acc 7#ahij72 van ,la>1 ibid41 #ae1 #deg 7#ahid72 ,g4 ,n4 ,lewis1 ,j4 ,am4 ,*em4 ,soc41 #cj1 #fge 7#aijh71 & ,wa%burn1 ibid41 #cb1 #fec 7#aiaj74 ,an admirable review ( ! !ories ( osmotic pressure1 by ,lovelace1 w be f\nd 9 ! ,am4 ,*em4 ,j41 #ci1 #edf 7#aijh7 7,/ud474 p#jcc ,,*apt] ,,iv ,,! ,,!ory ,,( ,,ionization2 ,,ionization ,,& ,,electrical ,,conductivity ,( ! laws & hypo!ses conc]n+ gases1 ! "o t is p]haps ( mo/ importance to *emi/ry is ,avogadro's hypo!sis4 ,) ! aid ( ?is hypo!sis1 we are able to det]m9e ! relative molecul> weights#di ( su* elem5ts & comp\nds z are gases1 or are volatile at high] temp]atures4 ,if equal volumes ( gases1 "u ! same conditions ( temp]ature & pressure1 conta9 ! same numb] ( molecules1 !n ! weights ( su* equal volumes also repres5t ! relative weights ( ! molecules compos+ ! gases4 ,z a /&>d1 = express+ ! relative molecul> weights 9 def9ite numb]s1 ! molecul> weight ( oxyg5 is tak5 by conv5tion to be #cb1 & all o!r molecul> weights are express$ 9 t]ms ( ?is /&>d4 ,! d5sity1 or weight ( "o lit] ( oxyg5 at #j & #gfj mm41 is #a4dbi grams1 & ! molecul> weight express$ 9 grams 7mol> weight7 ( oxyg51 #cb grams1 occupies1 !re=e1 #cb _/ #a4dbi1 or #bb4d lit]s4 ,! weights ( ?is same volume1 #bb4d lit]s1 ( gases & vapors1 calculat$ = #j & #gfj mm4 pressure1#ej express !n directly1 9 t]ms ( ! oxyg5 /&>d1 ! relative molecul> weights ( ! elem5ts or comp\nds =m+ ! gases4 ,! weights !mselves give u directly _! gram-molecul> or mol> weights4 ,:5 molecul> weights are det]m9$ 9 ?is way1 ) ! aid ( ,avogadro's hypo!sis1 results are obta9$ :i* agree p#jcd p]fectly ) ! *emical behavior ( ! comp\nds or elem5ts 9 "q4 ,! molecul> weights ( hydrog5 *loride1 wat]1 ammonia1 & m>% gas1 = in/ance1 are f\nd to be #cf4e1 #ah1 #ag & #af1 respectively1 correspond+ to ! =mul#ea ,h,cl1 ,h#b,o1 ,,nh#c & ,,*#d1 & 9 confirmation ( ^! results we f9d1 by me?ods us$ especially 9 organic *emi/ry1 t ^! comp\nds %[ a *emical behavior agree+ p]fectly ) ! pres5ce ( "o1 two1 ?ree & f\r hydrog5 atoms1 respectively1 9 _! molecules4 ,m>% gas1 = in/ance1 by treatm5t ) *lor9e1 yields a mono*loride1 ,,*#c;,cl1 a di*loride1 ,,*#b;,cl#b1 a tri*loride 7*lor(orm71 ,c,h,cl#c1 & a tetra*loride1 ,c,cl#d4 ,wat]1 by prop] treatm5t1 may be conv]t$ 9 successive /ages into alcohol1 7,c#b;,h#e7,,oh1 & !n into e!r1 7,c#b;,h#e7,o7,c#b;,h#e71 or into sodium hydroxide1 ,na,o,h1 & sodium oxide1 ,na#b,o4 ,x is ?is p]fect agreem5t betwe5 ! *emical behavior & ! =mul 7z bas$ on ^! molecul> weights & on ! analysis ( comp\nds71 :i* =ms ! /ronge/ exp]im5tal evid5ce ( ! correctness ( ! fundam5tal assumption ( ,avogadro's hypo!sis4 ,! agreem5t has be5 %[n to hold = innum]able comp\nds1 ev5 = ^? ( greate/ complexity1 & x 0 su* agreem5t :i* f9ally l$ to ! g5]al acceptance ( ! hypo!sis4 ,! exp]im5tal evid5ce ( ?is nature is s /rong1 s ext5sive & s completely corroborative ( ! hypo!sis1 t _m *emi/s1 r ju/ly1 consid] ! hypo!sis to h be5 e/abli%$ z a law1 al?\gh ! evid5ce is circum/antial r ?an direct4 ,:ile ! application ( ,avogadro's hypo!sis ?us gives results agree+ well ) ! obs]v$ *emical behavior ( v _m important comp\nds1 obs]vations h be5 made :i*1 at fir/ sight1 d n appe> to agree ) ! requirem5ts ( ! hypo!sis & :i* seem to raise a d\bt z to ! univ]sal tru? ( its fundam5tal assumption4 ,?us1 if equal volumes ( hydrog5 *loride & ammonia1 ( ! same temp]ature & pressure1 are br\ght toge!r1 ammonium *loride is =m$1 bo? gases be+ totally consum$4 ,s9ce1 accord+ to ! hypo!sis1 equal volumes1 "u ! conditions obta9+1 conta9 ! same numb]s ( molecules1 ! =mation ( ammonium *loride takes place accord+ to ! equation ,,nh#c ,h,cl ,,nh#d;,cl1 & we %\ld anticipate t ! molecul> weight ( p#jce ammonium *loride w\ld be #ag #cf4e or #ec4e4 ,h[ev]1 :5 ! molecul> weight is det]m9$ by obta9+ ! weight ( a measur$ volume ( ammonium *loride vapor1 at a temp]ature suffici5tly high to vaporize ! salt1 & ! obs]vations are r$uc$ to /&>d conditions ( temp]ature & pressure1 #bf4ge grams is f\nd z ! calculat$ weight ( #bb4d lit]s1 & ?is weight1 accord+ to ?is hypo!sis1 %\ld be ! molecul> weight ( ! *loride4 ,?is contradiction 9 two conclusions1 ea* rea*$ by ! application ( ,avogadro's hypo!sis to exp]im5tal obs]vations1 w\ld1 at ! fir/ glance1 make "o hesitate to accept ! hypo!sis z repres5t+ a univ]sal tru?2 x might seem z if 9 "s gases1 su* z ammonium *loride vapor1 !re might be only half z _m molecules 9 a giv5 volume z 9 ! same volume ( ! majority ( gases4 ,gase\s ,dissociation4--,! discrepancy betwe5 ! two conclusions & any d\bt z to ! univ]sal s\ndness ( ! great g5]alization express$ 9 ,avogadro's hypo!sis disappe>1 h[ev]1 9 ! light ( a clos] /udy ( ! composition ( ammonium *loride vapor4 ,x 0 sugge/$ simultane\sly by ,cannizz>o1 by ,kopp & by ,kkul#eb t ! abnormally l[ result1 obta9$ = ! molecul> weight ( ammonium *loride f a /udy ( its vapor d5sity1 is due to ! dissociation ( ! salt at high temp]atures into its compon5ts1 ammonia & hydrog5 *loride1 ! av]age ( ^: molecul> weights is1 9 fact1 7#ag #cf4e7 _/ #b1 or #bf4ge1 ! value f\nd exp]im5tally = ! vapor ( ammonium *loride4 ,pro( ( ! correctness ( ?is int]pretation 0 furni%$ by ,pbal1#ec :o %[$ t ammonium *loride vapor does consi/ ( ! two gases1 ! light] ( :i*1 ammonia1 diffuses m rapidly ?r\gh por\s walls 7,pbal us$ an asbe/os /opp]7 ?an does ! heavi]1 hydrog5 *loride4 ,! dissociation may be easily demon/rat$ by us+ an air cu%ion z a por\s wall4#ed ,f ! mixture produc$ by vaporiz+ ammonium *loride1#ee ! ammonia w diffuse m rapidly ?r\gh ! lay] ( air ?an w ! hydrog5 p#jcf *loride1 & ! gases may be recogniz$ 9 succession by _! action on litmus pap] 7exp474 ,! gase\s dissociation ( o!r ammonium salts1 ( phosphorus p5ta*loride & p5tabromide 7,,px#e ,,px#c ,x#b71 & ( a numb] ( less common comp\nds1 has be5 demon/rat$ 9 simil> ways4 ,z a result ( ! /udy ( ea* case1 ! important conclusion has be5 rea*$ t1 z f> z our k goes1 !re are no exceptions to ,avogadro's hypo!sis1 & ?is hypo!sis seems !re=e to repres5t a univ]sal tru?4#ef ,molecul> ,weight ,det]m9ations 9 ,solution4--,van 't ,h(f's ext5sion ( ! ,avogadro ,hypo!sis1 s t x %all apply to solutes 9 dilute solutions1 is ! basis ( ano!r g5]al me?od ( greate/ value = det]m9+ molecul> weights4 ,equal volumes ( dilute solutions ( ! same osmotic pressure & ! same temp]ature conta91 accord+ to van 't ,h(f1 ! same numb]s ( dissolv$ molecules1 irrespective ( ! solv5t us$4 ,fur!rmore1 ! numb] ( dissolv$ molecules is id5tical ) t :i* a gas ( ! same pressure & at ! same temp]ature w\ld conta9 9 ! same volume4 ,to det]m9e ! molecul> weight ( a solute1 !re=e1 we may calculate1 f ! osmotic pressure1 ! temp]ature & ! conc5tration ( ! solution1#eg t weight ( ! solute :i*1 9 #bb4d lit]s ( ! solution1 at #j w\ld give #gfj mm4 osmotic pressure2 ! weight f\nd repres5ts1 9 grams1 ! molecul> weight ( ! solute 9 ! solution us$4 p#jcg ,! fact t all solv5ts & all solutes are includ$ 9 ?is hypo!sis1 ) ! sole limit+ condition t ! solution mu/ be dilute1 is "o ( great significance & ( greate/ practical importance1 z we may use any suitable solv5t = det]m9ations4 ,:5 molecul> weights are det]m9$ 9 ?is way1 a v l>ge numb] ( comp\nds give ! same molecul> weight by ! solution me?od z by ! gas me?od4 ,= in/ance we h3 ,sub/ance4 ,mol4 ,wt4 ,mol4 ,wt4 ,solv5t4 ,gas ,me?od4 ,sol4 ,me?od4 ,*lor(orm1 ,c,h,cl#c #aai4e #aai4e ,b5z5e ,c>bon bisulphide1 ,,cs#b #gf #gf ,b5z5e ,me?yl 7wood7 alcohol1 ,,*#d,o #cb #cb ,wat] ,e?yl 7ord9>y7 alcohol1 ,c#b;,h#f,o #df #df ,wat] ,e!r1 ,c#d;,h#aj,o #gd #gd ,acet4 ,acid ,fur!r1 ! molecul> weight ( glucose is f\nd 9 aque\s solutions to be #ahj1 con=m+ to ! =mula ,c#f;,h#ab,o#f1 & agree+ ) ! molecul> weight z obta9$ by a *emical /udy ( comp\nds d]iv$ f glucose4 ,:ile !re are1 !n1 v _m agreem5ts 9 ! molecul> weights det]m9$ by ! solution & by ! old] me?ods1 x 0 recogniz$1 at ! outset1#eh t !re is also a l>ge numb] ( app>5tly abnormal cases1 9 :i*1 9 p>ticul>1 mu* l[] molecul> weights are obta9$ by ! solution me?ods ?an by ! gas me?od1--l[] ev5 ?an ! weights consi/5t ) ! accept$ atomic weights ( ! elem5ts 9 ! comp\nds 9 "q4#ei ,= in/ance1 we f9d #cf4e to be ! molecul> weight ( hydrog5 *loride 9 ! gas =m1 b 9 aque\s solution its app>5t molecul> weight1 z det]m9$ on ! basis ( van 't ,h(f's hypo!sis1 is n ev5 a con/ant2 x is f\nd to be less ?an #cf4e & approa*es ! limit #ah4be1 ! m dilute ! solution1 p#jch ! l[] be+ ! app>5t molecul> weight4#fj ,= sodium *loride1 ! =mula weight1 correspond+ to ! =mula ,na,cl1 is #eh4e4 ,?is w\ld also repres5t its smalle/ molecul> weight 9 gas =m1 consi/5t ) ! accept$ atomic weights = sodium & *lor9e4 ,9 aque\s solution1 aga91 ! app>5t molecul> weight ( sodium *loride is f\nd to be less ?an #eh4e1 & m ?an #bi4be1 ! value f\nd dep5d+ on ! conc5tration ( ! solution us$4 ,= z9c *loride we h1 likewise1 9 aque\s solution values mu* less ?an #acf & t5d+ t[>d ! limit #de1 :]eas ! =mula weight = ,zn,cl#b is #acf4 ,^! are in/ances ( a v l>ge class ( app>5t gross discrepancies betwe5 ! requirem5ts ( ! ,avogadro-van 't ,h(f pr9ciple & ! g5]ally accept$ molecul> weights ( common comp\nds4 ,!re are ?ree ways1 9 p>ticul>1 9 :i* "o might be incl9$ to reg>d su* results3 9 ! fir/ place1 "o might be tempt$ to consid] t van 't ,h(f's ext5sion ( ,avogadro's hypo!sis to solutions is ju/ifi$ 9 a consid]able numb] ( cases1 b n z a univ]sal expression1 applicable to all dilute solutions4 ,?is seems1 inde$1 to h be5 van 't ,h(f's own attitude orig9ally4 ,su* a view1 s9ce x does n ?r[ new light on ! matt]1 b simply %elves ! "q ( ! s\rce ( ! discrepancy1 w\ld be t5able only aft] all o!r explanations _h be5 f\nd unsatisfactory4 ,9 ! second place1 we might be incl9$ to consid] :e!r a molecule l hydrog5 *loride is n dissociat$ 9 aque\s solution into two small] molecules1 hcl1 9 :i* hydrog5 & *lor9e w\ld appe> z atoms ) ! weights h #j4e & cl #ag4ge1 :i* are half z l>ge z ! atomic weights det]m9$ f a /udy ( volatile comp\nds ( hydrog5 & *lor9e4 ,if we rememb] t our atomic weights are confess$ly maximum weights1 & n m9imum weights--al?\gh !y are almo/ c]ta9ly also ! true atomic weights--su* a view w\ld be1 at lea/1 wor?y ( "s consid]ation4 ,b1 9 ! fir/ place1 x w\ld be extraord9>y t we %\ld nev] h f\nd1 9 ! ?\s&s ( p#jci hydrog5 d]ivatives t h be5 inve/igat$1 any comp\nd1 ! molecule ( :i*1 9 ! gase\s condition1 conta9$ a s+le su* atom ( hydrog51 ) ! weight #j4e1 or an unev5 multiple ( x3 t only ev5 multiples or pairs h#b1 correspond+ to ! atom ,h1 %\ld always h be5 f\nd4 ,9 ! second place1 su* an explanation ( ! results ( ! molecul> weight det]m9ations 9 aque\s solutions giv5 above1 w\ld soon lead to difficulties1 :i* make ! view altoge!r unt5able4 ,= in/ance1 ! molecule ( z9c *loride1 accord+ to ! data giv51 w\ld h to break d[n into ?ree molecules &1 if ^! 7 ( uni=m composition1 we w\ld h to assume *lor9e atoms two-?irds or "o-?ird z l>ge z ,cl4 ,s9ce a mom5t ago we _h to assume *lor9e atoms "o-half z l>ge z ,cl1 we w\ld h to conclude t ! atomic weight ( *lor9e c\ld be1 at mo/1 ,cl _/ #f1 :i* is ! l>ge/ common divisor ( ,cl _/ #b & ,cl _/ #c4 ,no *emi/ w\ld s]i\sly consid] an atomic weight = *lor9e "o-six? z l>ge z ! accept$ weight1 = t w\ld mean t1 9 all ! *lor9e comp\nds inve/igat$ 9 ! condition ( gases1 we h always at lea/ six su* atoms occurr+ toge!r1 & o!rwise always multiples ( six4 ,consequ5tly su* an int]pretation ( ! s-call$ abnormal behavior ( solutions ( hydrog5 *loride1 sodium & z9c *lorides1 etc41 al?\gh at "o "t advanc$ by "s *emi/s1 mu/ be consid]$ z altoge!r unt5able4 ,a ?ird explanation ( ! abnormally l[ molecul> weights1 :i* c]ta9 sub/ances 9 aque\s solutions possess1 is1 t ! molecules ( ^! comp\nds are capable ( dissociation into small] molecules ( unlike composition1 some:at l ammonium *loride :5 x is heat$1 & t ! sub/ances 9 "q are dissociat$ m or less consid]ably 9 ?is fa%ion 9 ! solutions "u consid]ation4 ,hydrog5 *loride1 = in/ance1 besides exi/+ z su* 7z ,h,cl71 9 aque\s solutions1 might be capable ( dissociat+1 & actually be dissociat$1 to a consid]able degree into molecules conta9+ ei!r only hydrog5 or only *lor9e 7,h,cl ,h ,cl72 ! av]age ( ! weights ( ! molecules 9 a mixture ( molecules1 ,h,cl1 ,h1 & ,cl1 w\ld be less ?an #cf4e1 &1 accord+ to ! proportion ( dissociat$ & undissociat$ molecules ( hydrog5 *loride1 ! av]age w\ld lie betwe5 ! limits #cf4e & 7#a #ce4e7 _/ #b1 or #ah4be4 ,su* an p#jdj explanation1#fa made ) c]ta9 additions & re/rictions1 0 advanc$ 9 #ahhe by ,arrh5ius1 a ,sw$i% *emi/ & physici/1 :5 he le>n$ ( ! exceptional behavior ( ^! solutions1 z not$ by van 't ,h(f4 ,al?\gh at fir/ ?is int]pretation occasion$ consid]able criticism1 x has ma9ta9$ itself successfully = tw5ty ye>s1 on ! basis ( a wide range ( accumulat$ facts1 & x has be5 ( rem>kable value & b5efit 9 ! developm5t ( all bran*es ( *emi/ry & ! alli$ sci5ces4 ,! ,!ory ( ,ionization4--,arrh5ius#b made ! simple obs]vation t all ^? solutions1 9 :i* ! dissolv$ comp\nds seem to h abnormally l[ molecul> weights1 are solutions ?r\gh :i* an electric curr5t may be readily pass$1 !y are electrolytes1 :]eas ! solutions :i* give normal results 7see1 = in/ance1 ! table on p4 #cg7 d n all[ ! ready passage ( a curr5t1 !y are nonelectrolytes4 ,,exp4 ,! fundam5tal diff]5ce betwe5 ! two classes ( solutions may readily be demon/rat$4 ,to wat] conta9$ 9 an electrolytic cell1 :i* is connect$ ) a light+ circuit & ) an electric lamp1 fir/ "s alcohol1 & lat] a small quantity ( hydro*loric acid are add$4 ,! lamp is se5 to gl[1 in/antly1 :5 ! acid is add$4 ,?is simple fact1 t ! v solutions :i* give abnormally l[ molecul> weights = ! dissolv$ comp\nds are also good conductors ( electricity1 0 expla9$ by a !ory ( electrolytic dissociation or ( ionization1 :i* ,arrh5ius _h develop$#fb f a /udy ( ! conductivity ( electrolytes4 ,! same fact has aid$ 9 e/abli%+ ?is !ory :i* has l$ to ! elucidation ( vital problems ( electrical conductivity & to a successful p#jda explanation ( ! problem ( ! app>5tly abnormal osmotic pressures 7& molecul> weights7 ( electrolyte solutes4 ,x has ?us remov$ ! la/ difficulty 9 ! way ( accept+ ! van 't ,h(f-,avogadro ,hypo!sis 7p4 #ae7 z true = all dilute solutions1 exactly z ! discov]y ( gase\s dissociation made x possible to recognize 9 ! orig9al ,avogadro ,hypo!sis a univ]sal tru? 7p4 #cf7 ab\t gases4 ,& to ^! results 0 add$1 *iefly z ! fruit ( ! "w ( ,o/wald1 ) ! aid ( ! !ory ( ,arrh5ius1 ! mo/ successful & accurate =mulation ( ! problem ( ! *emical activity ( electrolytes1 kn[n 9 ! hi/ory ( *emi/ry4 ,ma9 ,assumptions ( ,arrh5ius's ,!ory ( ,ionization4--,! ma9 assumptions ( ! !ory ( electrolytic dissociation or ionization are ! foll[+3 7#a7 ,:5 an ionog5 is dissolv$ 9 wat]1 its molecules are imm$iately1 m or less completely1 dissociat$ by ! wat] into small] fragm5ts or molecules ( unlike composition4 7#b7 ,^! new molecules are *>g$ ) electricity2 ! molecules ( ! "o product are *>g$ ) positive1 ! molecules ( ! o!r product#fc ) negative electricity1 ! unit positive *>ge be+ equal 9 quantity1 b opposite 9 k9d1 to ! unit negative *>ge2 ! sum ( all ! positive *>ges 9 a solution is equal to ! sum ( all ! negative *>ges1 & ! :ole solution is electrically neutral4 7#c7 ,! dissociation is a rev]sible reaction1 & all electrolytes mu/ be consid]$ to be completely ioniz$ at inf9ite dilution4 7#d7 ,except = ! dep5d5ce result+ f ! electrical *>ges & ! consequ5t attractions & repulsions betwe5 ions1 ! ions mu/ be consid]$ indep5d5t molecules ) _! own specific *emical & physical prop]ties4 ,:5 a curr5t is pass$ ?r\gh ! solution ( an ionog51 ! electrifi$ p>ticles c>ry _! *>ges to ! electrodes 7see p#jdb bel[74 ,!y are call$ ! ions#fd ( ! electrolyte2 ! positively *>g$ ions are di/+ui%$ z cations f ! negatively *>g$ anions1 & ! electrode t[>d :i* ! cations move is call$ ! ca?ode 7negative electrode71 & ! electrode to :i* ! anions move is call$ ! anode 7positive electrode74 ,! dissociation ( hydrog5 *loride may be express$1 9 ! t]ms ( ! assumptions made1 9 ! foll[+ equation3 ,h,cl ,h ,cl2 t is1 hydrog5 *loride is dissociat$1 to a great] or small] ext5t & 9 rev]sible fa%ion1 into positively *>g$ hydrog5 ions ,h1 & negatively *>g$ *loride ions ,cl1 & ! *>ge on ea* *loride ion is equal 9 quantity to ! positive *>ge on ea* hydrog5 ion4 ,z9c *loride is dissociat$ accord+ to ! equation ,zn,cl#b ,zn#b #b ,cl1 &1 accord+ to 7#b71 ! *>ge on ea* z9c ion is twice z great 9 quantity z ! *>ge on ea* *loride ion1 & !re=e twice z great also z ! *>ge on ea* hydrog5 ion 7see bel[1 p4 #eh74 ,x is practically c]ta91 accord+ to m rec5t results1 t ! ions are comb9$ ) wat] to =m hydrates1 su* z ,h7,h#b,o7x & ,cl7,h#b,o7y4#fe ,?is does n modify1 ess5tially1 ! fundam5tal assumptions ( ! !ory1 b contributes r to a satisfactory explanation ( ! rle ( wat] z an ioniz+ ag5t1 a "q to :i* we %all return lat]4 ,! ,!ory ( ,ionization & ! ,electron ,!ory ( ,electricity & ( ,matt]4#ff--;,accord+ to ! views held by _m lead+ physici/s at ! pres5t "t1 negative electricity consi/s ( ultimate p>ticles ( matt] call$ electrons or corpuscles4 ,! mass ( an electron is ab\t #a _/ #ajjj ! mass ( an atom ( hydrog51 & ! electric *>ge ( ! electron is equal to t c>ri$ by a *loride ion 9 solution4#fg ,! atoms ( ! elem5ts are consid]$ to consi/ ( aggregations ( l>ge numb]s ( electrons 9 a k9d ( %ell or body ( positive electricity4 ,?is positive electricity1 9 a giv5 atom1 is equal 9 quantity to ! total negative *>ge ( ! electrons 9 ! atom1 ! atoms z su* p#jdc conta9+ no excess ( ei!r positive or negative electricity4 ,! numb] ( electrons 9 ! atom ( an elem5t is consid]$ to be def9ite & con/ant = t elem5t1 b ! numb] v>ies z we g f ! atoms ( "o elem5t to ^? ( a second elem5t1 ! numb] increas+ ) ! atomic weight ( ! elem5t4 ,"o ( ! mo/ fundam5tal & mo/ *>act]i/ic prop]ties ( elem5ts is consid]$ to be ! aff9ity :i* _! atoms %[ = electrons2 ?us1 ! atoms ( metals l sodium & potassium1 :i* are g5]ally call$ electropositive elem5ts1#fh %[ an enorm\s t5d5cy to lose "o electron ea* & to =m positively *>g$ p>ticles#fi ,na- 7 ,na7 & ,k- 7 ,k74#gj ,! atoms ( /rongly electronegative elem5ts1 l *lor9e1 h a trem5d\s t5d5cy = ga9+ & hold+ electrons beyond ! numb] orig9ally 9 su* atoms4 ,?us1 *lor9e atoms t5d to assume an electron ea*2 !y !reby become negatively *>g$ p>ticles1 ,cl 7 ,cl74 ,on ! basis ( ^! views1 we h 9 sodium *loride ,na,cl a sub/ance1 ^: molecules conta9 an atom1 ,na1 ) a trem5d\s t5d5cy to lose an electron1 & an atom1 ,cl1 :i* has a trem5d\s aff9ity = an electron4 ,x is natural to suppose1 !n1 t bo? t5d5cies w be satisfi$ by ! passage ( an electron f ! sodium to ! *lor9e atom1 ,na,cl ,na-,cl4 ,or1 if we use ! sign to designate ! positive *>ge produc$ on an atom by ! loss ( an electron & ! sign to indicate ! *>ge ga9$ ?r\gh ! assumption ( an electron1 we h#ga3 ,na,cl is ,na,cl4 ,simil>ly we h 9 hydrog5 *loride ,h-,cl or ,h,cl4 ,x is altoge!r likely1 !re=e1 t ! atoms 9 a molecule ( sodium *loride or ( hydrog5 *loride already possess electric *>ges1#gb s t1 ev5 :ile comb9$1 p#jdd _! t5d5cies to lose or ga9 electrons are satisfi$4 ,x is also possible t ! atoms are held toge!r 9 ! molecule by ! electrical attraction ( ! opposite *>ges4#gc ,! =ce ) :i* opposite electrical *>ges attract ea* o!r dep5ds1 z is well kn[n1 on ! nature ( ! surr\nd+ m$ium4 ,n[1 :5 molecul> sodium *loride or hydrog5 *loride is dissolv$ 9 wat] 7a favorable m$ium71 a decid$ decrease 9 ! attraction 7see p4 #fb71 betwe5 ! *>g$ atoms )9 ! molecules is br\ght ab\t1 & a process ( ionization results3 ,h,cl ,h ,cl4 ,! *>g$ p>ticles are call$ ions only aft] !y h sep>at$ f "o ano!r & h become indep5d5t molecules1 capable1 = example1 ( mov+ 9 opposite directions4 ,:ile ! atoms ( "s metallic elem5ts t5d to lose a s+le electron & =m ions ,me 7e4g4 ,na1 ,k71 ! atoms ( o!r elem5ts t5d to lose two or m electrons1 =m+ bival5t ions1 ,me#b 7e4g4 ,zn#b1 ,fe#b1 etc471 or trival5t ions1 ,me#c 7e4g4 ,bi#c1 ,fe#c71 & s =?4 ,simil>ly1 atoms ( ! s-call$ negative elem5ts may assume two or m electrons1 =m+ bival5t ions1 ,x#b 7e4g4 ,s#b71 & s =?4 ,! ,validity ( ! ,!ory ( ,ionization4--,9 det]m9+ ! validity ( ! !ory ( ionization1 we may consid]1 fir/1 ! suffici5cy ( ! explanations :i* x (f]s = obs]v$ facts & important ph5om5a4 ,we may !n weigh1 m critically1 by any evid5ce (f]+ itself1 ! facts :i* w enable u to decide betwe5 ?is !ory & ! old] !ory ( ionization1 t ( ,clausius 7p4 #ea74 ,! latt]1 al?\gh displac$1 is /ill (t5 reviv$ by oppon5ts ( ! mod]n !ory4 ,su* facts z we w consid] are f\nd1 fir/1 9 ! doma9 ( conductivity ph5om5a1 next1 9 ! osmotic pressure & relat$ prop]ties ( solutions1 &1 f9ally1 9 ! /udy ( ! *emical activity ( electrolytes 7see ,*apt] ,v74 ,ionization & ,electrical ,conductivity4--,turn+ our att5tion fir/ to ! field ( electrical ph5om5a1 & develop+ ! !ory = ! pres5t descriptively1 we f9d t ! conductivity ( a solution dep5ds1 accord+ to ?is !ory1 on ! fact t :5 two oppositely *>g$ poles are plac$ 9 a solution1 ! p#jde positive *>ge on ! anode attracts all ! negative p>ticles )9 its field ( action1 & repels all ! positive p>ticles1 exactly z a positive /atic *>ge ( electricity w\ld attract a negatively *>g$ pi?-ball & repel a positively *>g$ "o4 ,9 ! case ( a solution ( hydro*loric acid1 ! negative *>ge on ! ca?ode w\ld attract ! hydrog5 ions & repel ! *loride ions1 & ! positive *>ge ( ! anode w\ld attract ! *loride ions & repel ! hydrog5 ions4 ,! net result w\ld be a migration ( all ! *loride ions ) _! negative *>ges t[>d ! anode1 & ( ! positively *>g$ hydrog5 ions t[>d ! ca?ode1--a fl[ or curr5t ( electricity be+ ?us produc$4 ,! fact1 !n1 t a curr5t ( electricity does readily pass ?r\gh su* a solution ( an ionog51 is easily und]/ood on ! basis ( ^! views4 ,illu/ration3 ,,fig4 #h4 ,,exp4 ,! migration ( ! ions ?r\gh\t ! :ole solution may be demon/rat$ by ! passage ( a curr5t ?r\gh a l>ge ,u-tube conta9+ a mixture ( a cupric salt & a p]manganate1#gd plac$ "u "s dilute sulphuric acid4 ,! cupric-ion is blue1 all ioniz$ solutions ( cupric salts1 ) a colorless negative ion1 be+ blue1 :ile ! p]manganate-ion is ( an int5se purple color4 ,9 ! limb ( ! ,u-tube1 9 :i* ! ca?ode is plac$1 a blue zone1 conta9+ cupric ions1 is soon se5 em]g+ f ! purple liquid & ris+ t[>d ! ca?ode 7see ,fig4 #h74 ,x w take "s "t = any cupric ions actually to rea* ! electrode & be deposit$ z metallic copp]4 ,on ! anode side1 purple p]manganate ions are se5 ris+ t[>d ! positive electrode4 ,! movem5t ( ! electrically *>g$ p>ticles 9 opposite directions ?r\gh ! solution con/itutes an electric curr5t1 & su* a curr5t has ! prop]ties ( a curr5t ?r\gh a p#jdf wire--produc+1 = in/ance1 heat1 or be+ capable ( deflect+ a magnet plac$ 9 its field ( action4#ge ,electrolysis4--,:5 ions t\* an electrode1 !y are dis*>g$1 & ) ! dis*>ge1 are *ang$ *emically1 &1 accord+ to ! electron !ory1 also mat]ially4 ,cupric ions1 ,cu#b or ,cu#b 1 receiv+ two electrons at ! ca?ode1 are precipitat$ z metallic copp]4 ,:5 a curr5t is pass$ ?r\gh a solution ( hydro*loric acid1 ! hydrog5 ions1 by ! pair+ ( ! dis*>g$ ions1 yield hydrog5 gas consi/+ ( molecules1 ,h#b2 ! *loride ions are conv]t$ at ! anode into *lor9e ,cl#b4 ,! =mation ( ^! molecules1 ,x#b1 may be v>i\sly int]pret$1 z result+ ei!r f ! union ( two dis*>g$ or neutral atoms1 or z consi/+1 = in/ance 9 ! case ( hydrog51 9 ! dis*>ge ( a hydrog5 ion ,h1 at ! negative electrode1 foll[$ by ! assumption ( a negative *>ge or electron by ! neutral atom1 ! new ion ,h comb9+ at once ) ! positive ion ,h to =m ! molecule ,h,h4 ,at ! positive pole1 by an analog\s re*>g+ ( a dis*>g$ negative *loride-ion ,cl1 we %\ld obta9 a positive ion1#gf ,cl1 & imm$iately ! =mation ( ,cl#b or ,cl,cl w\ld foll[4 ,helmholtz advocat$ ! latt] conception ( ! action at ! electrodes1 &1 m rec5tly1 ,j4 ,j4 ,?omson#gg br+s =w>d1 z a v important argum5t 9 favor ( x1 ! fact t iod9e1 :i* accord+ to vapor d5sity det]m9ations dissociates into monatomic molecules at high temp]atures 7,i#b #b ,i71 becomes1 simultane\sly ) ?is dissociation1 also an excell5t gase\s conductor ( electricity1 z w\ld be anticipat$ f a dissociation1 ,i,i ,i ,i4 ,?is fact is emphasiz$ "h1 because 9 x we seem to h a case ( conductivity co9cid+ ) gase\s dissociation1 ! exi/5ce ( :i* is recogniz$ by ! univ]sally accept$ laws ( gases1 & diff]+ 9 no important respect f ! dissociation assum$ = conductors 9 solution4 ,conductivity & ,dilution4--,! passage ( a curr5t ?r\gh an electrolyte consi/s1 !n1 9 a transf] ( electricity by mat]ial p>ticles1 ! ions4 ,accord+ to ! !ory ( ionization only p#jdg ! ioniz$ portion ( an electrolyte c c>ry ! curr5t at any mom5t1 &1 consequ5tly1 a giv5 weight ( an ionog5 %\ld1 "u comp>able conditions1 be ! m effici5t z a conductor1 ! m completely x is dissociat$ into ions4 ,if ! conductivity ( a giv5 weight ( hydrog5 *loride1 = in/ance1 is measur$ "u comp>able conditions1 x %\ld be f\nd to be great]1 ! m completely ! acid is ioniz$4 ,n[1 9 aque\s solutions1 hydrog5 *loride ionizes "u ! influ5ce ( ! solv5t wat] 7pp4 #da1 #fa71 & ! !ory w\ld lead u to anticipate t ! great] ! proportion ( wat] us$1 ! m ext5sively w x ionize ! acid4 ,consequ5tly1 ! addition ( wat] to a giv5 weight ( acid %\ld increase ! latt]'s effici5cy z a conductor4 ,?is conclusion has be5 fully v]ifi$ by exact me?ods ( measurem5t & may be readily demon/rat$ by ! foll[+ s]ies ( exp]im5ts3 ,,exp4#gh ,an electrolytic cell1 hav+ ! %ape ( a p>allelopip$on & a capacity ( ab\t "o lit]1 is fitt$ ) electrodes ( copp]1 :i* rea* f ! bottom to ! top ( ! cell & are connect$ ) a /orage cell & an ammet]4 ,! cell is fir/ fill$ ) di/ill$ wat]3 no p]ceptible curr5t passes ?r\gh ! wat] & ! latt] is !re=e practically a nonconductor4 ,! cell is !n empti$ by means ( a siphon & #bj c4c4 ( #d-mol> hydro*loric acid is br\ght into x4 ,! ammet] %[s t a def9ite curr5t passes ?r\gh ! solution 7#j4ag amp]e 9 an exp]im5t#gi ) a cell #d4f cm4 wide & #aa4e cm4 long1 ) copp] electrodes #d4f cm4 broad & #ba cm4 high74 7,see ,fig4 #i1 p4 #dh47 p#jdh ,illu/ration3 ,,fig4 #i4 ,! conductivity ( a solution1 l t ( a metal conductor1 is ! reciprocal ( its resi/ance4 ,s9ce1 accord+ to ,ohm's law1#hj ! curr5t = a giv5 pot5tial is inv]sely proportional to ! resi/ance1 ! curr5t is also directly proportional to ! conductivity4 ,! resi/ances ( ! metal connections & ( ! ammet] 9 ! exp]im5t are v small comp>$ ) ! resi/ance ( ! solution1 & !y may be consid]$ negligible = our purpose4 ,?us1 ! curr5t indicat$ by ! ammet] is a closely approximate measure ( ! conductivity ( ! solution4 ,n[1 if a volume ( wat] 7#bj c4c47 equal to ! volume ( acid1 7 to be add$ to ! latt]1 ! cross section ?r\gh :i* ! curr5t fl[s f plate to plate w\ld be d\bl$1 &1 s9ce ! conductivity ( a liquid conductor1 l t ( a metal1 increases proportionally to ! cross section1 ! curr5t %\ld be d\bl$ by ! *ange 9 ?is "o factor4 ,on ! o!r h&1 ! conc5tration ( ! conduct+ acid is n[ "o-half ( ! orig9al conc5tration1 & ?is %\ld 9 turn r$uce ! conductivity ( ! solution to "o-half4 ,consequ5tly1 if !re 7 no fur!r *ange 9 ! electrolyte1 ! orig9al conductivity %\ld be ma9ta9$ :5 ! acid is ?us dilut$4 ,b1 accord+ to ! !ory ( ionization1 z has j be5 %[n1 ! addition ( p#jdi wat] to a giv5 weight ( hydro*loric acid %\ld increase ! proportion ( ioniz$ acid1 & s9ce ! ions are ! c>ri]s ( ! curr5t1 ! conductivity ( ! solution %\ld be increas$ because ( ?is *ange 9 ! composition ( ! electrolyte4 ,exp]im5t %[s t su* is ! case4 ,,exp4 #bj c4c4 ( wat] is add$ to ! #bj c4c4 ( #d-mol> acid 9 ! cell1 & ! mixture is /irr$4 ,! curr5t is decid$ly increas$ 7f #j4ag to #j4bb amp]e 9 ! exp]im5t "u discussion74 ,if #dj1 #hj1 #afj & #cbj c4c4 ( wat] are add$ 9 succession to ! cont5ts ( ! cell1 ! conductivity is increas$ by e addition ( wat]4 ,b1 :ile ea* addition dilutes ! acid to "o-half ! previ\s conc5tration1 ! increase gr[s proportionally small] & small] ) increas+ dilution4 ,9 ! foll[+ table1 ,ratios ,i are ! ratios ( ! obs]v$ conductivities to ! orig9al conductivity1 ,ratios ,,ii ! ratio ( ea* obs]v$ conductivity to ! prec$+ "o4 ,conc5tration ,obs]v$ ,ratios ,i4 ,ratios ,,ii4 ( ,acid4 ,conductivity4,a #d-mol> #j4ag #a #a4 #b-mol> #j4bb #a4cj #a4cj #a-mol> #j4bf #a4ec #a4ah #j4e-mol> #j4cj #a4gf #a4ae #j4be-mol> #j4ca #a4hc #a4jd #j4abe-mol> #j4cb #a4hh;,b #a4jc ,,table ,,notes3 ,a4 ,?is is an artificial scale 7see text7 ( conductivities1 & does n repres5t reciprocal ohms1 ! /&>d units ( conductivity4 ,b4 ,9 ! exact data on ! conductivities ( #d-mol> & #a_/h-mol> ,h,cl 7,kohlraus* & ,holborn1 ,leitv]mg5 d] ,elektrolyte 7#ahih7 p4 #afj71 ! ratio #cdh _/ #aha4e1 or #a4ib1 is f\nd1 9 place ( #a4hh z obs]v$4 ,we %\ld expect1 fur!r1 t ! increase 9 conductivity1 be+ dep5d5t on ! increas$ dissociation ( a f9ite quantity ( electrolyte1 %\ld t5d t[>ds a limit1 a maximum conductivity be+ rea*$ :5 7practically7 all ! acid is ioniz$4 ,z a matt] ( exp]i5ce1 ! conductivity ( a giv5 quantity ( an acid or o!r ionog5 does t5d t[>d a limit4 ,9 ! exp]im5t j made1 ! conductivity ( ! acid increases v rapidly at fir/1 z ! #d-mol> acid is dilut$ by wat]2 b ! increase 9 conductivity ) ! succe$+ dilutions gr[s small] & small] & ! conductivity is pla9ly approa*+ p#jej a limit 7see ! ratios ,i & ,,ii 9 ! table74 ,= hydro*loric acid at #ah1 ! limit = "o mole#ha 7#cf4e grams ,h,cl7 at inf9ite dilution1 z d$uc$ f ! curve ( conductivities at f9ite dilutions1 is #chd reciprocal ohms4#hb ,degree ( ,ionization ( an ,electrolyte4--,! conductivity ( a giv5 weight ( an electrolyte1 = in/ance ( its gram-equival5t weight1 dep5ds1 !n1 at a giv5 temp]ature on ! ext5t to :i* x is ioniz$1 ! ions be+ ! only c>ri]s ( ! curr5t 9 a solution ( an electrolyte4 ,! conductivity w also dep5d on ! friction :i* ! ions mu/ ov]come 9 mov+ ?r\gh a solution1 b1 = suffici5tly dilute solutions 9 a giv5 solv5t1 ! friction may be assum$ to be approximately con/ant = giv5 ions4 ,= su* solutions1 !n1 ! conductivity ( a giv5 weight ( a giv5 electrolyte at a giv5 temp]ature may be said to dep5d :olly on ! ext5t to :i* ! electrolyte is ioniz$4 ,?us1 ! proportion ( ioniz$ electrolyte 9 a solution may be det]m9$ by measur+ ! conductivity4 ,! extreme limit ( its conductivity1 calculat$ = inf9ite dilution1 repres5ts complete ionization ( ! electrolyte accord+ to a fundam5tal po/ulate 7 #c1 p4 #da7 ( ! !ory ( ,arrh5ius1 & ! ratio ( ! conductivity 9 a giv5 solution to ! conductivity ( ! same weight ( electrolyte at inf9ite dilution repres5ts !n ! proportion ( ioniz$ electrolyte to ! total electrolyte us$4 ,?is proportion is call$ its degree ( ionization 7commonly designat$ by 74 ,if we call v ! conductivity ( a gram-equival5t weight ( an electrolyte 9 a giv5 solution1 & ! limit ( its conductivity = inf9ite dilution1 !n ! degree ( ionization is f\nd f v _/ 4 p#jea ,! me?od ( calculation ( 9 a specific case may be illu/rat$ z foll[s3 ! resi/ance ( a cube ( #a cm4 edge ( a solution ( hydro*loric acid1 :i* conta9s #a4hbe grams hydrog5 *loride 9 a lit]1 is f\nd to be #ee4ee ohms at #ah4 ,its conductivity !n is #a _/ #ee4ee reciprocal ohms4 ,n[1 #a4hbe grams ( hydrog5 *loride is #a4hbe _/ #cf4e or #a _/ #bj gram-equival5t ( ! acid2 a :ole gram-equival5t ( ! acid w\ld be conta9$ 9 #bj lit]s or #bj1jjj c4c4 ,!n v 7#a _/ #ee4ee7 #bj1jjj1 or #cfj reciprocal ohms4 ,if we use ! value at inf9ite dilution giv5 above1 #cfj _/ #chd1 or #ic4ge4 ,t is1 #ic4ge ( ! hydro*loric acid is pres5t 9 ! ioniz$ condition 9 su* a solution1 & #f4be is n ioniz$4 ,by mak+ ! assumption t at inf9ite dilution electrolytes are completely ioniz$1 & by tak+ ! ratio :i* ! equival5t conductivity ( a giv5 solution ( an electrolyte be>s to ! maximum limit-value 7calculat$ = ! conductivity at inf9ite dilution7 to be ! degree ( ionization ( ! electrolyte1 z j expla9$1 ! !ory ( ,arrh5ius has ?us made x appe> possible to det]m9e exp]im5tally ! proportion ( ioniz$ electrolyte pres5t4 ,x is a significant fact t ! equival5t conductivity ( hydro*loric acid is close to its limit ev5 at f9ite dilutions1 & t ! same relation holds = ! /rong acids & ! /rong bases1 9 g5]al1 & = mo/ salts4 ,b ! equival5t conductivity ( weak acids1 l acetic acid1 & ( weak bases1 l ammonium hydroxide1 9 f9ite dilutions is /ill f> remov$ f ! limits :i* may be calculat$ = inf9ite dilutions4 ,arrh5ius 0 l$ !n to ! fur!r important conclusion t1 9 ! case ( ! fir/ electrolytes m5tion$1 a v l>ge proportion ( ! electrolyte mu/ exi/ 9 ! ioniz$ =m at f9ite conc5trations1 _! equival5t conductivities hav+ almo/ rea*$ ! limit *>act]i/ic ( inf9ite dilution4 ,clausius's ,!ory ( ,ionization & ! ,mod]n ,!ory4--,x is 9 ^! conclusions--9 p>ticul> t ! proportion ( ioniz$ electrolyte may be det]m9$ exp]im5tally1 & t frequ5tly a l>ge proportion is f\nd to be ioniz$ at f9ite conc5trations1--t ! mod]n !ory ( ionization diff]s f ! old] !ory ( ,clausius4 ,! =m] is an elaboration ( ! latt]1 & "s oppon5ts#hc ( ! mod]n !ory /ill uphold ! latt] z (f]+ an adequate explanation ( ! ph5om5a ( conductivity4 ,all facts1 !n1 9 p>ticul>1 :i* confirm ! validity ( ! conception ( ! degree ( ionization1 z introduc$ by ,arrh5ius1 p#jeb mu/ be consid]$ z crit]ia favor+ 8 !ory1 specifically4 ,! developm5t ( *emi/ry 9 ! la/ tw5ty ye>s is replete ) su* evid5ce & we %all meet x 9 _m connections ?r\gh\t our "w4 ,clausius#hd also assum$ dissociat$ molecules or ions to be ! real c>ri]s ( electricity 9 ! passage ( a curr5t ?r\gh ! solution ( an electrolyte1 b he assum$ only a m9ute quantity ( ^! molecul> fragm5ts or ions to be free at any mom5t1 _! exi/5ce be+ suppos$ to be transitory & dep5d5t 9 p>ticul> on ex*anges ( atoms betwe5 molecules4 ,z a result ( ! oscillations ( ! atoms compos+ a molecule1 oscillations comp>able ) ! motions ( molecules assum$ 9 ! k9etic !ory ( gases1 molecules 7 consid]$ by ,clausius occasionally to rea* su* a condition ( in/ability1 t !y dissociat$ into small] p>ticles2 s9ce ! atoms 7 suppos$ to be held 9 a molecule by attractions ( electrical *>ges on ! atoms 7!ory ( ,b]zelius71 ! fragm5ts ( ! molecule w\ld c>ry ! *>ges1 positive & negative respectively1 :i* !y possess$ 9 ! molecule4 ,su* a break+ up or dissociation ( molecules 01 fur!r1 suppos$ to occur ) p>ticul> ease dur+ ! collisions ( molecules1 ! electrical attractions & repulsions ( ! *>g$ atoms favor+1 at su* mom5ts1 an ex*ange ( atoms4 ,dur+ ! ex*ange1 ! atoms 7 consid]$ to be free molecules1 *>g$ ) electricity--ess5tially ions1--capable ( mov+ "u ! influ5ce ( electrical =ces & ( ?us c>ry+ a curr5t4 ,f9ally1 su* ions 7 suppos$1 9 "p1 to escape recomb9ation1 & to rema9 free1 until ea* ion ei!r collid$ & comb9$ ) an ion ( opposite *>ge1 or collid$ ) a molecule & displac$ an atom ( ! same *>ge f t molecule1 a new ion be+ ?us lib]at$4 ,! !ory1 z usually int]pret$1 assum$ ! exi/5ce ( only a v small quantity ( su* free ions1 t be+ all t 0 suppos$ to be requir$ to expla9 ! facts kn[n at ! "t x 0 advanc$4 ,9 :at foll[s1 we %all conf9e ! discussion /rictly to su* contra/s betwe5 ! two !ories z gr[ out ( a consid]ation ( ! ph5om5a ( conductivity1 & p>ticul>ly consid] "s evid5ce :i* is directly conc]n$ ) ! conductivity ( solutions4 ,9 ! fir/ place1 if ! =mation ( ions occurs prim>ily dur+ ! ex*ange ( atoms 9 collisions ( molecules1 !n1 z ,:e?am#he has %[n1 ! specific conductivity 7( #a cm4#c7 ( an electrolyte1 l hydro*loric acid1 mu/ increase ) ! conc5tration & mu/ increase1 approximately1 z a function ( ! ?ird p[] ( ! conc5tration4 ,! m conc5trat$ ! solution1 ! m frequ5t ! collisions betwe5 ! dissolv$ molecules mu/ be4 ,z a matt] ( fact1 z %[n 9 ! foll[+ table1 ! conductivity p#jec increases a little less ?an proportionally to ! fir/ p[] ( ! conc5tration--:i* is 9 conflict ) ! assumption made 9 ! hypo!sis ( ,clausius1 b 9 p]fect agreem5t ) ! hypo!sis ( ,arrh5ius4 ,! small decrease ) increas+ conc5tration1 9 ! simple ratio betwe5 conductivity & conc5tration1 is due to ! decreas+ degree ( ionization 9 ! m conc5trat$ solutions1 z dem&$ by ! hypo!sis ( ,arrh5ius4 ,! table gives1 9 ! fir/ column1 ! specific conductivities ( hydro*loric acid at #ah1 &1 9 ! second column1 ! conc5trations2 ^! conc5trations are express$ 9 moles or gram-equival5ts p] cubic c5timet]2 ! la/ column gives ! ratio ( conductivity to conc5tration4 ,conductivity ,conductivity ( #a c4c4 ,conc5tration ,conc5tration4 #j4jjcgj #j4jjjja #cgj #j4jjgcd #j4jjjjb #cfg #j4jajib #j4jjjje #cfd #j4jahjj #j4jjjje #cfj #j4jceaj #j4jjjaj #cea ,fur!rmore1 facts admitt$ by ,clausius to be inexplicable by 8 own assumptions receive1 9 ! !ory ( ,arrh5ius1 at lea/ a quantitative =mulation borne out by a mass ( corroborative evid5ce4 ,! diff]5ce 9 conductivity betwe5 pure wat] & sulphuric acid is su* a fact1 m5tion$ by ,clausius4 ,det]m9ations ( ! ionization ( sulphuric acid & ( wat]1 by ! conductivity me?ods :i* are bas$ on ! !ory ( ,arrh5ius1 %[ t1 :ile sulphuric acid is v consid]ably ioniz$ 7see p4 #ajd71 wat] is sc>cely ioniz$ at all4 ,! ionization ( wat] 7see p4 #ajd7 has be5 det]m9$ quantitatively by at lea/ f\r indep5d5t me?ods ( exam9ation1#hf &1 m9imal z ! ionization is1 ! results agree s well ) ea* o!r t van 't ,h(f#hg 0 l$ to write3 ,if "o is n previ\sly conv9c$ ( ! correctness ( ! !ory ( electrolytic dissociation1 h>dly any result won by means ( x is s conv9c+1 z ! agreem5t betwe5 ! conclusions rea*$ 9 completely diff]5t ways z to ! degree ( dissociation ( wat] itself4 ,aft] su* an agreem5t1 x is h>dly conceivable t ! basis on :i* all ^! results re/ %\ld fur!r be alt]$4 ,mobilities or ,p>tial ,conductivities ( ,ions3 ,pr9ciple ( ,kohlraus*4--,if ions h a sep>ate exi/5ce1 ea* k9d ( ion w\ld be expect$ to move ?r\gh a solution "u a giv5 electrical =ce at a giv5 temp]ature ) its own specific spe$1 ! spe$ be+ presumably dep5d5t on ! nature ( ! ion z well z on ! weight ( wat] comb9$ ) x & dragg$ ) x ?r\gh ! solution 7p4 #db74 p#jed ,su* relative spe$s ( ions may be demon/rat$ by means ( an exp]im5t3 ! motion ( ! hydrog5 ions1 =m$ by ! ionization ( hydro*loric & o!r acids1 may be obs]v$ by _! action on a r$d5$ 7alkal9e7 solution ( ph5olph?alen1 :i* is decoloriz$ by !m2 & ! motion ( ! hydroxide ions1 =m$ by ! ionization ( sodium hydroxide & o!r bases1 may be foll[$ by _! action on colorless ph5olph?alen1 :i* turns r$ 9 _! pres5ce4 ,! hydrog5 & ! hydroxide ions are ! fa/e/1 9 aque\s solutions1 & _! spe$s are comp>$ 9 ! next exp]im5t ) t ( blue cupric ions1 :i* h a spe$ r\ghly ! same z t ( _m common ions4 ,9 ?is exp]im5t ! hydrog5 ions are readily se5 to move ab\t twice z fa/ z ! hydroxide ions & five to six times z fa/ z ! cupric ions4 ,illu/ration3 ,,fig4 #aj ,,exp4#hh ,five grams ( ag>-ag> are dissolv$ 9 #bej c4c4 ( boil+ wat]4 ,to #ajj c4c4 ( ! hot solution1 #cb c4c4 ( a saturat$ solution ( potassium *loride & ab\t #a c4c4 ( ph5olph?alen solution are add$1 toge!r ) en\gh ( a solution ( potassium hydroxide1 add$ drop by drop1 to produce a deep r$ t9t 9 ! ph5olph?alen4 ,( ?is mixture #ej c4c4 is treat$ ) dilute hydro*loric acid1 add$ drop by drop1 until ! r$ color is j dis*>g$1 & !n an excess ( acid1 equal 9 am\nt to ! quantity us$ to neutralize ! #ej c4c41 is add$ to ! mixture4 ,?is colorless solution & #ej c4c4 ( ! r$ solution are p\r$1 :ile /ill w>m1 into ! two p>ts ( a wide ,u-tube1 sl[ly & at equal rates1 s t ! level on ! two sides rema9s ! same4 ,9 ?is way x is possible )\t difficulty to h ! solution on "o side r$ 7alkal9e7 & on ! o!r side colorless 7acid74 ,! ag>-ag> is all[$ to congeal1 & !n a mixture ( #j4e c4c4 ( hydro*loric acid1 7sp4 g4 #a4ab71 #f c4c4 ( saturat$ cupric *loride solution & #bj c4c4 ( wat] is p\r$ ov] ! r$ half1 & a mixture ( #bj c4c4 ( saturat$ p#jee potassium *loride solution & #b c4c4 ( #aj potassium hydroxide solution is p\r$ ov] ! colorless half4 ,! ,u-tube is surr\nd$ by ice wat] dur+ ! passage ( ! curr5t1 & ! ca?ode is plac$ 9 ! solution on ! colorless side4 ,9 ,fig4 #aj ! ,u-tube is %[n :5 fir/ *>g$ 7on ! left71 & aft] ! curr5t has be5 runn+ = a %ort "t 7on ! "r74 ,! conductivity ( a solution mu/ be made up1 !re=e1 ( ! sum ( ! %>es :i* ! positive ions & ! negative ions1 respectively1 take 9 c>ry+ ! curr5t4 ,?is pr9ciple 0 fir/ advanc$ by ,kohlraus*4 ,! %>e ( ea* k9d ( ion 9 conduct+ a curr5t may be det]m9$1 = hydro*loric acid = in/ance1 9 ! foll[+ way3 ,a por\s diaphragm may be us$ to divide ! solution 9 an electrolytic cell into two halves1 ! conc5tration ( ! acid be+ ! same 9 bo? halves 7repres5t$1 z indicat$ 9 ,fig4 #aa1 by #ae molecules#hi ( ioniz$ acid 9 ea* half74 ,a measur$ curr5t is pass$ ?r\gh ! solution1 say1 suffici5t to lib]ate #c molecules ( hydrog5 ,h#b1 & #c ( *lor9e ,cl#b1 correspond+ to #f ions ( ea*1 & ! conc5tration ( ! acid 9 ea* half is !n aga9 det]m9$ by analysis4 ,say x is f\nd to correspond to #ad molecules ( hydro*loric acid 9 ! half ( ! solution on ! side ( ! ca?ode & #aj molecules 9 ! half on ! side ( ! anode 7see ,fig4 #ab74 ,!n ! anode half has lo/ #e ions ( hydrog51 :i* mu/ h pass$ ?r\gh ! diaphragm t[>d ! ca?ode & tak5 ! place ( five ( ! six hydrog5 ions dis*>g$ at ! ca?ode4 ,simil>ly1 ! solution ar\nd ! ca?ode has lo/ "o *loride ion1 :i* mu/ h pass$ ?r\gh ! diaphragm t[>d ! anode1 & ! hydrog5-ion correspond+ to x1 rema9+ on ! "r side )\t a comp5sat+ negative ion1 mu/ be ! six? hydrog5-ion dis*>g$ at ! ca?ode4 ,9 o!r words1 five hydrog5 ions pass$ to ! "r1 :ile "o *loride ion pass$ to ! left4 ,! hydrog5 ions !n c>ri$ five-six?s ( ! curr5t ?r\gh ! diaphragm1 & consequ5tly ?r\gh ! solution1 & ! *loride ions only "o-six? ( ! curr5t4 ,s9ce ! solutions 7 ( equal conc5tration to />t )1 ! hydrog5 ions h mov$ five times z fa/ t[>d ! ca?ode z ! *loride ions h mov$ t[>d ! anode4 ,illu/ration3 ,,fig4 #aa4 ,illu/ration3 ,,fig4 #ab4 ,! equival5t conductivity ( #j4a-mol> hydro*loric acid is #cea at #ah1 & exp]im5t %[s t ! hydrog5-ion c>ries #hd ( ! curr5t1 ! *loride-ion only #af4 ,! conductivity may !n be consid]$ to be ! p#jef sum ( ! %>e ! hydrog5-ion has 9 c>ry+ ! curr5t1 i4e4 #j4hd #cea1 or #bie1 & ( ! %>e ( ! *loride-ion1 #j4af #ceb4e1 or #ef4 ,^! values may be call$ ! equival5t p>tial conductivities or mobilities ( ! ions 9 ?is solution4 ,9 a simil> way1 ! conductivity ( e solution ( an electrolyte may be %[n to repres5t ! sum ( ! mobilities ( ! ions c>ry+ ! curr5t 7pr9ciple ( ,kohlraus*74 ,! limit ( ! conductivity ( "o equival5t ( an electrolyte is ! sum ( ! mobilities ( ! ions compos+ ! electrolyte4 ,! frictional =ces be+ con/ant = inf9itely dilute solutions1 at a giv5 temp]ature1 an ion w always %[ ! same mobility1 irrespective ( ! nature ( ! ion ( opposite *>ge1 ) :i* x =ms ! electrolyte4 ,we may !n put 7l l71 if l & l are us$ to designate ! limits ( ! mobilities ( gram-equival5ts ( ! positive & negative ions =m+ ! electrolyte4 ,! foll[+ table#ij gives ! limits ( ! mobilities = gram equival5ts ( "s ( ! mo/ important ions at #ah4 ,limits ( ,mobilities ( ,common ,ions at #ah4 ,k3 #fe4c ,ca3 #ec4j ,i3 #ff4g ,na3 #dd4d ,h3 #cah4j ,,no#c3 #fj4h 7,,nh#d73 #fd4b ,,oh3 #agd4j ,c#b;,h#c,o#b3 #cc4g ,ag3 #ee4g ,cl3 #fe4i ,,s#d3 #fi4g ,= q dilute solutions1 9 :i* ! friction may be assum$ to be approximately con/ant1 ! conductivity w dep5d1 n only on ! mobilities ( ! ions1 :i* may be tak5 to be ! same z = solutions ( extreme dilution1 b also on ! proportion ( electrolyte t is ioniz$1 i4e4 on ! degree ( ionization1 4 ,!n v 7l l71 :i* is an elaboration ( ! orig9al equation giv5 on page #ej4 ,n[1 ,kohlraus* discov]$ ! pr9ciple ( ! summation ( ! mobilities ( ions a numb] ( ye>s be=e ! !ory ( ,arrh5ius 0 advanc$1 & ! proportion 9 :i* ! ion is pres5t 9 a giv5 solution be+ unkn[n1 ! effect ( :at is "h kn[n z ! degree ( ionization 0 includ$ empirically 9 ! value ( ! mobility4 ,x is n surpris+1 !n1 t an ion 0 f\nd to h approximately ! same mobility only 9 solutions ( ! same conc5tration ( /rictly analog\s & closely relat$ salts1 :i*1 accord+ to pres5t me?ods ( inve/igation1 are n[ f\nd to h approximately ! same degree ( ionization4 ,= in/ance1 ! mobility ( ! gram-equival5t ( ! *loride-ion 0 f\nd to be approximately ! same1 #dg4c & #ej4e respectively1 9 mol> solutions ( sodium & potassium *loride at #ah1 no acc\nt be+ tak5 ( ! degrees ( ionization4 ,h[ev]1 ! degrees ( ionization ( ! two salts are approximately ! same1 #ff4i & #gd4i respectively1 & might be ignor$ 9 a comp>ison ( ! conductivities1 )\t affect+ ! result ( ! comp>ison 9 any m>k$ way4 p#jeg ,:5 ! conductivities ( unlike electrolytes are comp>$1 ! introduction ( ! conception ( ! degree ( ionization 7by ,arrh5ius17 into ,kohlraus*'s pr9ciple ( ! indep5d5t conductivities ( specific ions1 %[s mo/ /rik+ results & demon/rates ! value ( ! new conception4 ,= in/ance1 ! equival5t conductivity ( potassium *loride at #ah 9 #j4jge mol> solution is #aac4h reciprocal ohms & ! p>tial conductivity ( ! *loride-ion 9 ! solution is #eg4d4 ,b ! conductivity ( an equival5t solution ( m]curic *loride at #ah is only #a4ea1 :i* is v mu* less ?an ! conductivity ( ! *loride-ion alone 9 ! potassium *loride solution4 ,n[1 m]curic *loride1 accord+ to inve/igations ( its conductivities & ( its effect 9 depress+ ! freez+-po9t ( wat]1#ia is "o ( a v few salts t are difficultly ionizable 7p4 #ajg72 accord+ to ! data m5tion$1 x is ioniz$1 at mo/1 to ! ext5t ( #b4e p] c5t 9 ! solution 9 "q1 :]eas #hg4e p] c5t ( ! potassium *loride is ioniz$ 9 su* a solution4 ,:5 ! diff]5ce 9 ! degree ( ionization is tak5 into acc\nt1 ! conductivity :i* m]curic *loride %\ld %[ may be calculat$1 on ! assumption t ! *loride-ion has ! same mobility 9 ! two solutions1 b t !re is less ( x 9 ! m]curic solutions4 ,we put ,hg,cl#b 7l,hg l,cl7 #j4jbe 7#dh #fe4i7 #b4h4 ,we ?us f9d t ! conductivity ( ! m]curic *loride %\ld be1 approximately1 only #b4h reciprocal ohms1 :i* is ( ! same ord] z t f\nd 7#a4ea74ib ,9 ! same way1 :5 we comp>e ! conductivity ( a /rong acid1 l hydro*loric acid1 ) t ( a weak acid1 l acetic acid--! conductivity ( #j4a mol> hydro*loric acid is #cea1 ( #j4a mol> acetic acid only #d4f--! pr9ciple ( ! specific1 *>act]i/ic mobility ( ! hydrog5-ion1 :i* is pres5t 9 bo? solutions1 has significance only if we take into acc\nt ! v diff]5t conc5trations ( ! hydrog5-ion 9 ! two solutions1 result+ f ! diff]5t degrees ( ionization ( ! two acids--#ia = ! hydro*loric & only #a4g = ! acetic acid4 ,! same relations hold 9 ! comp>ison ( ! conductivity ( a solution ( a /rong base l sodium hydroxide ) t ( an equival5t solution ( a weak1 i4e4 mu* less ioniz$ base l ammonium hydroxide1 or 9 comp>+ ! conductivity ( a weak acid or a weak base ) ! conductivities ( _! mu* m highly ioniz$ salts4 ,9 all ^! cases ! use ( ! conception ( ! degree ( ionization ( ! electrolytes makes possible a mu* broad] & m g5]al application ( ! pr9ciple ( ! indep5d5t migration or mobility ( ! ions ?an 0 possible be=e ! !ory ( ,arrh5ius 0 propos$1 & m>ks a di/9ct advance 9 ! !ory ( conductivity1 ov] :at 0 possible on ! basis ( ! !ory ( ,clausius4 p#jeh ,f>aday's ,law4--,if a def9ite quantity ( electricity1 a f>aday1#ic or #if1fjj c\lombs1 is pass$ ?r\gh a solution ( hydro*loric acid1 a def9ite quantity 7#cf4e grams1 "o mole7 ( ! hydrog5 *loride is decompos$1 & "o gram ( hydrog5 & #ce4e grams ( *lor9e are lib]at$ by ! dis*>ge ( "o gram 7i4e4 "o gram-ion7 ( ! hydrog5-ion & #ce4e grams or "o gram-ion ( ! *loride-ion4 ,9 a solution ( cupric *loride1 ! *loride-ion is id5tical 9 e respect ) ! *loride-ion f\nd 9 a solution ( hydro*loric acid4 ,9 ! solution ( cupric *loride1 h[ev]1 a molecule ( ! salt1 :5 x is completely ioniz$1 produces two *loride ions = e cupric ion 7,cu,cl#b ,cu#b #b ,cl74 ,s9ce ! solution nev] %[s ! pres5ce ( an excess ( ei!r =m ( electricity1 & ! negative *>ge on ea* *loride ion is ! same z on a *loride ion =m$ by ! dissociation ( hydrog5 *loride1 a cupric ion mu/ hold exactly d\ble ! positive *>ge t a hydrog5 ion does4 ,9 mod]n t]ms1 ea* hydrog5 atom1 pres5t z an ion1 has lo/ "o electron1 & ea* copp] atom pres5t 9 ! =m ( a cupric ion has lo/ two electrons4 ,our unit quantity ( electricity1 #if1fjj c\lombs1 c dis*>ge !re=e only half z _m ( ! cupric z ( ! hydrog5 ions1 & s9ce ea* cupric ion is #fc4f times z heavy z ! hydrog5-ion 7,cu #fc4f1 ,h #a71 #fc4f _/ #b grams ( copp]1 ! equival5t weight1 w be deposit$ 9 place ( "o gram ( hydrog54 ,simil>ly1 f a solution ( f]r\s *loride ,fe,cl#b1 #ee4i _/ #b grams ( iron 7,fe #ee4i7 w be deposit$1 ! f]r\s ion be+ ,fe#b2 :ile f a solution ( f]ric *loride ,fe,cl#c1 only #ee4i _/ #c grams ( iron w be deposit$ by #if1fjj c\lombs1 ! f]ric ion1 ,fe#c1 hold+ ?ree times ! *>ge t a hydrog5 ion does4 ,9 o!r words1 a giv5 quantity ( curr5t w decompose equival5t quantities ( electrolytes & deposit equival5t quantities ( metals4 ,?is is ! well-kn[n law ( ,f>aday4 ,! !ory ( ,arrh5ius agrees ) x1 z did ! !ory ( ,clausius4 ,x _c be consid]$ z evid5ce be>+ on ! "q ( ! pref]5ce to be giv5 to ei!r ( ! !ories ( ionization1 s9ce ! degree ( ionization ( electrolytes is n involv$ 9 ! relations cov]$ by ! law4 ,b any o!r relation w\ld h be5 incompatible ) ! !ory ( ,arrh5ius4 ,! law is ( p>ticul> importance 9 giv+ u p#jei ! be/ clew t we h 9 reg>d to ! ultimate nature ( val5ce 7z %[n = in/ance 9 ! diff]5ce betwe5 ! f]r\s1 ,fe#b1 & ! f]ric ions1 ,fe#c74 ,on ! basis ( ?is law1 val5ce may be said to consi/ simply 9 ! capacity ( atoms to hold diff]5t multiples ( ! unit electrical *>ge 7positive or negative74 ,?is conception w be ( especial value to u :5 we come to consid] ! relation ( ! !ory ( ionization to oxidation & r$uction 7,*apt]s ,,xiv & ,,xv74 ,diffusion ( ,ions & ,conc5tration ,cells4--,:5 !1 app>5tly1 abnormally l[ molecul> weight ( ammonium *loride 0 expla9$ z be+ due to ! dissociation ( ea* molecule ( ammonium *loride into a molecule ( ammonia & "o ( hydrog5 *loride1 ! evid5ce ( ! correctness ( ?is int]pretation 0 at once =?com+--! vapor ( ammonium *loride1 by ! unequal rates ( diffusion ( its compon5ts1 0 prov$ to be a mixture ( ! two gases 7p4 #ce74 ,n[1 if an electrolyte l hydro*loric acid 9 aque\s solution is dissociat$ m or less into sep>ate ions1 ,h & ,cl1 !n "o may well ask1 :e!r ! dissociation _c be demon/rat$ by ! same k9d ( exp]im5t1 z1 = in/ance1 by %[+ t hydrog5 & *loride ions are molecules ) unequal p[]s ( diffusion & by sep>at+ !m by virtue ( su* inequality4 ,ions be+1 accord+ to ! !ory "u consid]ation1 indep5d5t molecules1 except = ! attractive & repulsive =ces ( ! electrical *>ges1 !y %\ld h1 l cane sug>1 copp] nitrate & o!r solutes1 ! capacity = diffusion f regions ( high] to ^? ( l[] conc5tration4 ,fur!r1 if ions %[ diff]5t degrees ( mobility 7p4 #ec71 "o w\ld expect ! m mobile or fa/] mov+ "o to diffuse m rapidly ?an a less mobile ion4 ,su* a relation %\ld hold = ! ions 9 a solution ( hydro*loric acid1 ! hydrog5-ion1 accord+ to ! calculations ( ,kohlraus*#id & ! obs]vation ( ,lodge1#ie mov+ at a rate ab\t five times z great z t ( ! *loride-ion1 at #ah4 ,?us1 if a r conc5trat$ solution ( hydro*loric acid 7 cov]$ ) a lay] ( wat]1 or ) a v dilute solution ( ! acid1 "o might expect ! hydrog5 ions to migrate fa/] ?an ! *loride ions f ! p#jfj po9t ( high] to t ( l[] conc5tration1 i4e4 f ! m conc5trat$ to ! dilute acid4 ,:5 ! exp]im5t is tri$ 9 ?is way1 no sep>ation ( ! hydrog5 f ! *loride ions seems to occur4 ,! reason = ! failure ( ! exp]im5t is z foll[s3 ,if any su* sep>ation did occur1 ev5 to ! ext5t ( say "o milligram-equival5t ( hydrog5 & *loride ions1 we w\ld h a sep>ation ( electro/atic *>ges ( #if c\lombs4 ,^! *>ges1 on ! small areas involv$1 w\ld inevitably produce enorm\s pot5tials1 t w\ld op]ate aga9/ ! sep>ation4 ,! hydrog5 ions1 :i* w\ld t5d to move f ! conc5trat$ to ! dilute acid1 w\ld !re=e be held back by ! p[]ful attraction betwe5 _! positive *>ges & ! negative *>ges left 9 ! conc5trat$ acid 7on ! ,cl ions74 ,! sep>ation ( ! electrical *>ges1 incid5tal to a fa/] diffusion ( hydrog5 ions1 if x occurr$1 w\ld result1 !re=e1 9 ! developm5t ( electrical =ces ( attraction1 :i* w\ld prev5t a sep>ation ( ! oppositely *>g$ p>ticles beyond any b di/ances too small to be measur$4 ,x w\ld foll[1 h[ev]1 t no difficulty :atev] %\ld be exp]i5c$ 9 obs]v+ su* a sep>ation1 z a result ( unequal rates ( migration ( ! ions 9 "q1 if provision 7 made to pres]ve electrical neutrality 9 all zones ( ! two solutions1 i4e4 if provision is made = ! imm$iate dis*>ge ( ! ions1 z !y sep>ate by ! unequal rates ( diffusion4 ,= in/ance1 ! "p ( ! liquid into :i* ! positive hydrog5 ions move m rapidly1 *>g+ x ) positive electricity1 may be connect$1 by means ( a wire1 ) ! "p ( ! liquid to :i* ! *loride ions1 left beh9d by _! sl[] movem5ts1 are imp>t+ a negative *>ge4 ,9 su* a circuit1 a curr5t ( electricity %\ld be produc$1 ! positive curr5t fl[+ ?r\gh ! wire f ! dilute to ! conc5trat$ acid4 ,z a matt] ( fact1 we f9d t a curr5t is produc$1 :5 ^! conditions are obs]v$4 ,,exp4 ,! l[] plate 9 an ,arrh5ius cell is cov]$ ) conc5trat$ hydro*loric acid4 ,v dilute acid is all[$ to fl[ sl[ly on to ! surface ( ! conc5trat$ acid1 f a pipette ) a curv$1 n>r[ po9t1 until ! upp] plate is subm]g$4 ,! two plates are connect$ ) a s5sitive galvanomet]4 ,! curr5t fl[s 9 ! direction dem&$ by ! obs]v$ mobilities ( ! ions1 ! positive curr5t ent]+ ! galvanomet] f ! plate cov]$ by ! dilute solution1 :i* is *>g$ positively by ! fa/] mov+ hydrog5 ions com+ f ! conc5trat$ solution4 ,if ! cell is p#jfa connect$ ) ! electrodes ( a v small cell conta9+ copp] sulphate1 9 ! c\rse ( tw5ty-f\r h\rs q a deposit ( metallic copp] is =m$ on ! electrode connect$ ) ! conc5trat$ solution ( hydro*loric acid4 ,! exi/5ce ( ! products ( ! electrolytic dissociation1 ( hydro*loric acid may !re=e be demon/rat$1#if by ! aid ( ! individual diffusion ( ! products ( ! dissociation1 9 ! same way z 0 ! coxi/5ce ( ! products ( ! gase\s dissociation ( ammonium *loride1 :5 ! conditions = ! exp]im5t are adapt$ to ! nature ( ! dissociation products4 ,cells ( ?is type1 dep5d+ = _! curr5t on unequal conc5trations ( giv5 ions1 are call$ conc5tration cells4 ,if x c be %[n t ! fl[ ( electricity1 result+ f su* unequal diffusibility ( ions1 is a function n only ( ! diff]5ce 9 ! total conc5tration ( ! electrolyte 9 ! two solutions br\ght into contact ) ea* o!r1 b is also a function ( ! relative degrees ( ionization ( ! electrolyte 9 ! two solutions1 z def9$ by ! !ory ( ,arrh5ius1 !n ?is me?od ( exp]im5tation may be us$ z a fur!r te/ ( ! validity ( ?is !ory z aga9/ t ( ,clausius4 ,x is obvi\s t if su* curr5ts are ! results ( ! diffusion ( ions f high] to l[] conc5trations1 !n ! ess5tial conc5trations d n embrace all ( ! electrolyte1 b only ! ioniz$ "p4 ,w4 ,k4 ,lewis#ig has r rec5tly %[n t ! degrees ( dissociation ( electrolytes may be measur$ by ! use ( conc5tration cells1 & t ! results agree well ) ! det]m9ations ( ! degree ( dissociation f conductivity measurem5ts 7p4 #ej74 ,f calculations1 bas$ on ,jahn's accurate measurem5ts ( ! electromotive =ces ( conc5tration cells1 ,a4 ,a4 ,noyes#ih f9ds t :5 ! conductivity ratio is assum$ to repres5t ! degree ( ionization ( ! salt1 ! calculat$ values ( ! electromotive =ce ( conc5tration cells exce$ ! measur$ ones by only ab\t "o p] c5t1 9 ! case ( potassium & sodium *loride betwe5 ! conc5trations ( #a _/ #fjj & #a _/ #bj mol>4 ,! ,rle ( ! ,solv5t 9 ,ionization4--,a "q t has pr(\ndly int]e/$ *emi/s1 p>ticul>ly dur+ ! la/ few ye>s1 has be5 t ( ! rle :i* ! solv5t plays 9 ! p#jfb dissociation ( electrolytes into ions4 ,! mo/ important ioniz+ solv5t is wat] &1 ( ! common solv5ts :i* cause ionization1 x is ! mo/ p[]ful 9 ?is p>ticul>4 ,alcohols h also ioniz+ p[]2 me?yl or wood alcohol1 :i* /&s ne>e/ to wat]1 has a high] ioniz+ p[] ?an ord9>y e?yl alcohol4 ,! exact "w#ii ( ,frankl9 & ,kraus1 on ! conductivity ( solutions ( salts 9 liquid ammonia1 %[$ t ! same g5]al relations obta9 = su* solutions z = solutions 9 wat]1 ! diff]5ces be+ diff]5ces ( degree r ?an ( k9d4 ,salts are f\nd to be less ioniz$ 9 liquid ammonia ?an 9 equival5t aque\s solutions1 b _! conductivities are high]1 ! result ( small] friction 9 ammonia4 ,liquid hydrog5 cyanide is also a v good ioniz+ m$ium4 ,solv5ts :i* cause ionization only to a m9imal ext5t are b5z5e 7,c#f;,h#f71 c>bon bisulphide1 e!r1 *lor(orm1 petroleum e!r 7gasol9e7 & simil> solv5ts4 ,hydrog5 *loride dissolv$ 9 b5z5e has an extremely small conductivity1 indicat+ only a trace ( ionization4#ajj ,! "q may be rais$1 :y ! fir/ solv5ts m5tion$ %\ld h ! p[] to cause ionization1 :ile ! second s]ies ( solv5ts nam$ d n h ?is p[]1 or h x only to a v slight ext5t4 ,)\t attempt+ to ent] into an elaborate discussion ( ?is important "q1 x may be said t ,j4 ,j4 ,?omson#aja & ,n]n/#ajb sugge/$ t ! ioniz+ p[]s ( solv5ts mu/ be intimately connect$ ) _! dielectric behavior1 & ?is view has n[ be5 well e/abli%$4 ,x may be said1 9 simple t]ms1 t ! s-call$ dielectric con/ant ( a solv5t det]m9es ! =ce ) :i* electrical *>ges w attract & repel ea* o!r2 ! high] ! dielectric coeffici5t ( a m$ium1 ! small] w be ! attraction betwe5 opposite electrical *>ges1 o!r conditions be+ ! same4 ,9 solv5ts1 !n1 ( high dielectric p[]s1 ! coxi/5ce ( oppositely *>g$ p>ticles mu/ be m favor$ ?an 9 solv5ts ( l[ dielectric p[]s4 ,! dielectric con/ants ( a numb] ( solv5ts are giv5 9 ! foll[+ table3 p#jfc ,hydrog5 cyanide1 ,,hnc #ie ,hydrog5 p]oxide1 ,h#b,o#b #ic ,wat]1 ,h#b,o #ha ,me?yl 7wood7 alcohol1 ,,*#d,o #cb ,e?yl 7ord9>y7 alcohol1 ,c#b;,h#f,o #bb ,ammonia1 ,h#c,n #bb ,*lor(orm1 ,c,h,cl#c #e ,e!r1 7,c#b;,h#e7b,o #d ,b5z5e1 ,c#f;,h#f #b ,x is q app>5t t ! good ioniz+ m$ia h1 z a matt] ( fact1 ! highe/ con/ants2 ^? :i* cause ionization1 at mo/ m9imally 7e4g4 b5z5e71 ! l[e/4 ,rec5t ext5d$ & exact inve/igations by ,wald5#ajc h succe$$ 9 br++ ! ioniz+ p[] ( solv5ts into def9ite quantitative relations to _! dielectric con/ants1 ) ! result t ord] has be5 br\ght out ( a condition ( *aos t1 = a numb] ( ye>s1 exi/$ 9 ?is field1 z ! result ( conclusions bas$ on incomplete data4 ,conductivity be+ a function bo? ( ! proportion ( dissociat$ electrolyte & ( ! mobility ( ! ions 9 a giv5 solution1 ,wald5 det]m9$1 = a c]ta9 salt 7an organic d]ivative ( ammonium iodide1 namely1 tetrae?yl ammonium iodide ,n7,c#b;,h#e7d;,i71 = all solv5ts us$1 n only ! conductivities = f9ite dilutions b also1 by extrapolation1 ! limit+ values = inf9ite dilution4 ,he 0 ?us able to det]m9e ! degree ( ionization ( ! salt4 ,"s ( 8 results are p>ticul>ly int]e/+2 = in/ance1 a poorly conduct+ solution1 su* z t ( ! salt 9 glycol1 a solv5t resembl+ glyc]9e 9 g5]al "*1 may conta9 ! dissolv$ electrolyte 9 a highly ioniz$ /ate1 :ile 9 a mu* bett] conduct+ solution ! degree ( ionization may be mu* small]--! l[ conductivity ( ! fir/ solution be+ ! result ( a v high friction & ( ! sl[ motion ( ! ions1 :ile ! well-conduct+ solution might %[ a v high degree ( mobility ( ! ions4 ,! mobility *anges ) ! nature ( ! solv5t1 & ! limit1 1 ( ! equival5t conductivity ( ! salt1 z f\nd by ,wald51 ranges f #h 9 glycol1 :i* is a ?ick1 visc\s oil l glyc]9e1 to #bjj 9 acetonitrile1 a ?9 mobile solv5t4 ,9 ! "o solution1 an obs]v$ conductivity ( #d repres5ts #ej ionization ( ! salt1 9 ! o!r only #b4 ,n[1 = solutions ( a giv5 electrolyte--tetrae?yl ammonium iodide 0 us$--,wald5#ajd f\nd ! foll[+ exce$+ly int]e/+ relation betwe5 ! ionizations 91 & ! dielectric con/ants (1 v>i\s solv5ts3 e#a 3 c#a e#b 3 c#b a con/ant1 :]e e#a & e#b repres5t ! dielectric con/ants ( diff]5t solv5ts1 & c#a & c#b repres5t ! conc5trations ( ! salt 9 ! solv5ts :5 ! salt is ioniz$ to ! same degree#aje 9 ! two solutions4 ,! be>+ ( ! relation is app>5t f ! data 9 ! foll[+ p#jfd table4#ajf ,! upp] half ( ! table gives ! dielectric con/ants 7column two7 ( ! solv5ts nam$ 9 column "o2 ! conc5trations :i* %[ id5tical degrees ( ionization--#dg--;are giv5 9 ! ?ird column1 & ! la/ column gives ! value ( ! relation e 3 c4 ,! l[] half ( ! table pres5ts ! same k9d ( data1 = ! same salt1 :5 its degree ( ionization is #ia1 9 ! diff]5t solutions exam9$4 ,x is cle> t ! numb]s 9 ! ?ird column ( ea* "p repres5t approximately con/ants4 ,all solutions1 includ+ aque\s solutions1 are ?us br\ght into "o g5]al relation4 ,solv5t4 e c e 3 c ,me?yl alcohol #cb4e #j4abe #fe ,e?yl alcohol #ba4g #j4jbj #hj ,acetyl bromide #af4b #j4jaj #ge ,b5zaldehyde #af4i #j4jaf #gh ,acetonitril #ce4h #j4ajj #gg ,wat] #hj #j4jjiaj #chc ,furfurol #ci4d #j4jjabe #cfe ,nitrome?ane #dj #j4jjabe #cga ,acetonitril #cf #j4jjajj #ceh ,me?yl alcohol #cb4e #j4jjjej #cfe ,! ,ioniz+ ,p[] ( ,solv5ts ,relat$ to ! ,unsaturat$ ,condition ( _! ,simple ,molecules & to _! ,p[] ( ,association4--,a c>eful scrut9y ( ! gr\p ( highly-ioniz+ solv5ts 7p4 #fb7 br+s out ano!r int]e/+ relation1 to :i* att5tion is call$ because x is a *emical "o1 & :i* %\ld always be consid]$ 9 connection ) reactions 9 su* solv5ts4 ,x is well kn[n t ammonia is an unsaturat$ body1 comb9+ readily ) all acids1 & ) _m salts1 su* z copp] sulphate4 ,! fact may be recall$1 t ?is unsaturat$ condition is ascrib$ to ! unsaturat$ nitrog5 atom 9 ! molecule ( ammonia1 ! nitrog5 %[+ a val5ce ( only #c 9 ammonia1 :]eas 9 ! d]ivatives x =ms :5 x saturates itself ) ! comp\nds m5tion$1 e4g4 9 ,h#d,n,cl1 x has five saturat$ val5ces4 ,assum+ t a val5ce consi/s 9 a unit *>ge1 positive or negative1 on ! atom 7pp4 #db1 #ei71 a view :i* has almo/ become a c]ta9ty1 we %\ld decide t ! two free val5ces 9 ammonia mu/ consi/ ( a negative & a positive *>ge1 z express$ 9 ,h#c,n4 7,we may imag9e su* a d\ble p#jfe *>ge to be produc$ by ! movem5t ( "o electron ( ! nitrog5 atom to a position 9 t atom :i* w\ld make "o po9t ( ! atom negative & ! o!r positive47 ,z a matt] ( fact1 we f9d ammonia unit+ ) hydrog5 *loride1 by absorb+ a positive & a negative fragm5t ( x--produc+ ,h#d,n,cl f ,h#c,n ,h ,cl4 ,x is also evid5t t1 ?r\gh ^! *>ges1 ammonia c\ld comb9e ) itself to =m l>g] complexes1 ,,nh#c-,,nh#c1 9 :i* we w\ld /ill h two opposite *>ges1 presumably remov$ fur!r f ea* o!r ?an 9 ! simple molecule4 ,! new molecule c\ld1 9 turn1 by virtue ( its *>ges1 comb9e ) a fur!r molecule to =m a /ill l>g] or m associat$ molecule1 ,,nh#c-,,nh#c-,,nh#c1 & su* association c\ld evid5tly g /ill fur!r4 ,"o c readily see t su* molecules w\ld be electrically pol>iz$1 & _! *>ges might easily h ! p[] to cause#ajg electrolytic dissociation or ionization4 ,! l>g] ! associat$ molecule1 ! fur!r ap>t might be ! positive & negative *>ges ^u x3 ! fur!r ap>t ! *>ges1 ! small] w\ld be _! mutual attraction3 & ! small] ! mutual attraction1 ! /rong]1 presumably1 w\ld ! dissociat+ p[] ( su* a molecule be4 ,! dissociation may be effect$1 possibly1 by ! action ( ^! int5sifi$ *>ges ^u *>ges already exi/+#ajh )9 ! molecule ( ! dissolv$ ionog54 ,9 liquid ammonia we might well h1 = in/ance1 ! action ,,nh#c-,,nh#c ,h,cl 7,,nh#c-,,nh#c7;,h ,cl1 or ,,nh#c-,,nh#c ,h,cl 7,,nh#c-,,nh#c7;,h ,cl4 ,n[1 9 liquid ammonia1 ! salts ,,nh#d;,cl1 ,,nh#d,,no#c or1 m probably1 7,,nh#c7x,h,cl1 7,,nh#c7x1,,hno#c h ! functions ( ! aque\s acids#aji2 t is1 ! hydrog5-ion ( ! acids is f\nd comb9$ ) ! solv5t ammonia4 ,! ion 7,,nh#c-,,nh#c7;,h1 & simil> ions 9 liquid ammonia1 w\ld correspond !n to :at is consid]$ ! hydrog5-ion 9 aque\s solutions#aaj 7=m$ accord+ to ,h,cl ,h ,cl1 z ord9>ily writt571 & ! pol>iz$ *>ges on molecules l ,,nh#c-,,nh#c appe> ?us z possible active ag5ts 9 ?is dissociation ( ! hydrog5 *loride molecules4 p#jff ,n[1 x is a significant fact t all ! be/ ioniz+ solv5ts are comp\nds ^: simple molecules are unsaturat$ exactly l ^? ( ammonia2 ?is is true = wat] ,h#b,o1 ! unsaturat$ "* ( ^: oxyg5 atom is n[ univ]sally recogniz$4 ,x is n[ a famili> fact t liquid wat] is n repres5t$ by ! =mula ,h#b,o b consi/s ( m complex molecules 7,h#b,o7n4 ,accord+ to ! mo/ rec5t inve/igations1#aaa :ile /eam is ,h#b,o1 or monohydrol1 ice is trihydrol 7,h#b,o7#c1 & liquid wat]1 at ord9>y temp]atures1 a mixture consi/+ *iefly ( dihydrol 7,h#b,o7#b1 "s trihydrol1 & v little monohydrol4 ,! proportion ( ! la/ appe>s to increase ) a rise ( temp]ature2 ! proportion ( trihydrol seems to increase ) a fall 9 temp]ature4 ,"o c easily see h[ su* aggregates w\ld result f ! saturation ( ! free *>ges on oxyg51 by fur!r molecules ( wat]4 ,"o c also see t su* an association ( wat] molecules c\ld leave a positive & a negative *>ge on ! associat$ molecules1 :i* w\ld be pol>iz$ & m effective ?an ! simple molecule w\ld be4 ,t ! molecule ( hydrog5 cyanide conta9s a simil>ly unsaturat$ atom 0 demon/rat$ by ,nef4#aab ,he prov$ t ! behavior ( hydrocyanic acid agrees ) ! /ructure express$ by ! =mula ,,hn,c1 :i* we may well write ,,hn,c4 ,9 sulphur dioxide1 ano!r good ioniz+ solv5t1 we h1 simil>ly1 unsaturat$ sulphur1 ! sulphur atom be+ "h quadrival5t1 :]eas its maximum val5ce is six4 ,n[1 ! ioniz+ p[] ( solv5ts l wat]1 ammonia1 etc41 has be5 ascrib$1 by v>i\s *emi/s1 n only to _! dielectric prop]ties1 b also to ! unsaturat$ condition ( _! molecules1 & p>ticul>ly to _! p[]s ( association into l>ge molecules4 ,! relations develop$ sugge/ t all ?ree prop]ties are mo/ intimately relat$1 ! dielectric prop]ties & ! p[]s ( association be+ consequ5ces1 possibly1 ( ! fundam5tal condition ( unsaturation1 & ( ! great t5d5cy t[>d self-saturation1#aac ( ! simple molecules ( ! be/ ioniz+ solv5ts4 ,f ,wald5's "w x appe>s t ! dielectric con/ant f9ally det]m9es ! quantitative ioniz+ effect ( a solv5t4 ,,footnotes3 #di ,f ! molecul> weights ( elem5ts & comp\nds1 ! atomic weights ( elem5ts may be det]m9$1 ) ! aid ( analysis4 7,cf4 ,smi?1 ,inorganic ,*emi/ry 7#aiji71 p4 #aif1 or ,g5]al ,*emi/ry = ,colleges 7#aijh71 p4 #acj 7,/ud471 or ,rems51 ,inorganic ,*emi/ry1 ,advanc$ ,c\rse 7#aijd71 pp4 #ga-hj 7,/ud4747 #ej ,! weight ( a small volume ( a gas or vapor1 at any def9ite temp]ature & pressure1 is det]m9$4 ,) ! aid ( ,boyle's & ,gay-,lussac's laws1 ?is obs]v$ volume is !n r$uc$ to /&>d conditions4 ,f9ally1 ! weight ( #bb4d lit]s1 "u /&>d conditions1 is obta9$ by calculation4 #ea ,= ! d$uction ( =mul see ,smi?1 ,inorganic ,*emi/ry1 #aif1 #bjc2 ,college ,*emi/ry1 #dj2 or ,rems51 ibid41 p4 #gi 7,/ud474 #eb ,kopp1 ,liebig's ,ann41 #aje1 #cij 7#aheh72 ,kkul1 ibid41 #ajf1 #adc 7#aheh7 7,/ud474 #ec ,liebig's ,ann41 #abc1 #aii 7#ahfb7 7,/ud474 #ed ,wanklyn & ,robison1 ,compt4 r5d41 #eb1 #edi 7#ahfc7 7,/ud474 #ee ,= in/ance 9 a te/ tube held 9 a horizontal position4 #ef ,by apply+ ! corrections dem&$ by ! k9etic !ory 7van d] ,waals's equation7 to gases ev5 "u ord9>y pressures1 ,guye & ,d4 ,b]?ollet h obta9$1 ) ! aid ( ,avogadro's hypo!sis1 values = ! molecul> weights ( gases & = ! atomic weights ( _! compon5ts1 :i* comp>e 9 accuracy ) ! be/ analytical "w on solutions & solids4 #eg ,! usual exp]im5tal me?ods consi/ 9 det]m9+ ! elevation ( ! boil+-po9t1 or ! l[]+ ( ! freez+-po9t1 or ! l[]+ ( ! vapor t5sion ( a solv5t by a solute1 me?ods :i* 7 discov]$ by ,ra\lt & us$ empirically until van 't ,h(f develop$ _! relations to ! ,avogadro pr9ciple4 ,! calculation ( a molecul> weight is mu* simplifi$ by ! use ( ! diff]5t specific con/ants express+ ! l[]+ or elevation produc$ by "o gram-molecule or mole1 dissolv$ ei!r 9 "o lit] or 9 #ajj grams ( ea* specific solv5t4 #eh ,see ,arrh5ius1 ,z4 phys4 ,*em41 #a1 #fca 7#ahhg74 #ei ,or1 on ! basis ( ! accept$ molecul> weights1 abnormally high osmotic pressures1 abnormally great l[]+s ( ! freez+-po9t1 rais+s ( ! boil+-po9t1 etc41 7 obta9$4 ,van 't ,h(f1 orig9ally1 on acc\nt ( ^! discrepancies1 consid]$ ?is ext5sion ( ! ,avogadro ,hypo!sis to hold only = ! majority ( sub/ances 9 solution1 n = all 7,arrh5ius1 loc4 cit474 ,x 0 consid]$ to h univ]sal application 7= dilute solutions7 only aft] ,arrh5ius _h expla9$ ! exceptions ) ! aid ( 8 !ory ( electrolytic dissociation4 #fj ,t is1 hydrog5 *loride1 9 aque\s solution1 depresses ! vapor t5sion & ! freez+-po9t & elevates ! boil+-po9t consid]ably m ?an an equimolecul> quantity1 = in/ance1 ( glucose does1 & gives a consid]ably high] osmotic pressure4 ,! diff]5ces are relatively great]1 ! m dilute ! solutions us$4 #fa ,a f\r? int]pretation advanc$ at "o "t 9 opposition to ! !ory ( ionization is t salts l sodium *loride & z9c *loride are hydrolyz$ & !reby produce m solute molecules1 e4g4 ,na,cl ,h#b,o ,na,o,h ,h,cl4 ,aside f ! fact t su* hydrolysis ( salts1 :5 x does occur 7,*apt] ,x471 is easily detect$1 & t x c be prov$ n to occur appreciably 9 ! case ( sodium *loride 7loc4 cit471 ?is int]pretation fails utt]ly to acc\nt = ! results obta9$ ) acids1 e4g4 ,h,cl1 ,,hno#c1 ,h#b,,s#d1 & ) bases1 e4g4 ,na,o,h1 ,ba7,,oh7#b1 :i* 9 aque\s solutions %[ an increase 9 ! numb] ( molecules z great z %[n by salts4 ,?is explanation is !re=e unt5able4 #fb ,z4 phys4 ,*em41 #a1 #fca1 7#ahhg74 ,previ\s pap]s 7 publi%$ 9 ! transactions ( ! ,royal ,academy ( ,sw$5 7,/ockholm74 ,= a hi/ory ( ! !ory see ,o/wald1 ,z4 phys4 ,*em41 #fi1 p4 #a 7#aiji71 & ,arrh5ius1 ,! ,will>d ,gibbs ,address1 ,j4 ,am4 ,*em4 ,soc41 #aiaa 7,/ud474 #fc ,9 ! case ( d\ble salts1 su* z sodium-ammonium phosphate1 & simil> comp\nds1 ! dissociation leads to ! =mation ( m ?an two products4 ,! molecules ( two or m diff]5t products may !n be *>g$ positively &1 conv]sely1 !re may be two or m diff]5t products ( dissociation c>ry+ negative *>ges4 ,we h1 = in/ance1 ,na7,,nh#d7;,,hpo#d ,na ,,nh#d ,h ,,po#dc & ,na7,,nh#d7;,,hpo#d ,na ,,nh#d ,,hpo#db4 ,9 all cases ! rule conc]n+ ! sum ( all ! *>ges1 z express$ 9 7#b71 mu/ be fulfill$1 ! *>ge on ! phosphate ion1 ,,po#dc1 be+ ?ree times z great z t on a sodium1 ammonium1 or hydrog5 ion2 t on ! acid phosphate ion1 ,,hpo#db1 be+ twice z great4 #fd ,ion ! go+ or ! migrat+ p>ticle4 #fe ,see ,wa%burn1 ,j4 ,am4 ,*em4 ,soc41 #ca1 #cbb 7#aiji71 9 reg>d to ! values ( x & y1 ! quantities ( wat] c>ri$ by c]ta9 ions4 #ff ,vide ,j4 ,j4 ,?omson1 ,electricity & ,matt] 7#aije7 & ,corpuscul> ,!ory ( ,matt] 7#aijg7 7,/ud474 ,vide ,r4 ,a4 ,millikan1 ,sci5ce1 #cb1 #dcf 7#aiaj71 on ! discrete or granul> nature ( electricity 7,/ud474 #fg ,see ,millikan1 loc4 cit41 z to ! exact value ( ?is unit *>ge4 #fh ,cf4 ,mc,coy1 ,j4 ,am4 ,*em4 ,soc41 #cc1 ,m>*1 #aiaa1 9 reg>d to electropositive1 composite 7i4e4 nonelem5t>y7 metals4 #fi ,! symbol is us$ to designate an electron4 ,! loss ( "o electron by an atom leaves a unit positive *>ge on ! p>ticle4 #gj ,9 ,*apt] ,,xv 7q4 v47 ! aff9ity ( ! elem5ts = electrons & ! reactions1 ( ! nature ( oxidation & r$uction1 dep5d+ on ?is aff9ity1 are discuss$ 9 detail4 #ga ,j4 ,j4 ,?omson1 ,corpuscul> ,!ory ( ,matt]1 p4 #abj4 #gb ,a4 ,a4 ,noyes 7,c>negie ,in/itution ,publications1 ,no4 #fc1 p4 #cea 7#aijg771 believes t we may h two k9ds ( molecules1 ,h,cl & ,h,cl1 z well z ! ions ,h & ,cl4 #gc ,mod]n !ory ?us is rev]t+ to ! ,b]zelius !ory ( *emical aff9ity ,vide ,mey]'s ,hi/ory ( ,*emi/ry 7translat$ by ,m',g[an7 #ahia1 #bbj-bfe1 or ,lad5burg's ,hi/ory ( ,*emi/ry 7translat$ by ,dobb97 #aijj1 #hf1 #hh1 etc4 #gd ,to a saturat$ solution ( cupric nitrate may be add$ a small am\nt ( a saturat$ solution ( potassium p]manganate1 suffici5t to give a decid$ purple color to ! mixture4 ,potassium *romate1 z recomm5d$ by ,a4 ,a4 ,noyes1 may be us$ 9 place ( ! p]manganate4 7,cf4 ,noyes & ,blan*>d1 ,j4 ,am4 ,*em4 ,soc41 #bb1 #gbf 7#aijj747 #ge ,exp42 cf4 ,eck/e91 ,j4 ,am4 ,*em4 ,soc41 #bg1 #gei 7#aije7 7,/ud474 #gf ,w4 ,a4 ,noyes1 ,j4 ,am4 ,*em4 ,soc41 #bc1 #dfj 7#aija72 ,/ieglitz1 ibid41 #bc1 #gif 7#aija72 ,wald51 ,z4 phys4 ,*em41 #dc1 #che 7#aijc74 #gg ,corpuscul> ,!ory ( ,matt]1 p4 #acj 7#aijg74 #gh ,! exp]im5t is an adaptation ( a simil> "o describ$ by ,a4 ,a4 ,noyes & ,blan*>d1 ,j4 ,am4 ,*em4 ,soc41 #bb1 #gbf 7#aijj74 #gi ,! copp] electrodes are pol>iz$ by ! =mation ( hydrog5 on ! ca?ode1 b1 9 ! c\rse ( a few seconds1 ! curr5t becomes r con/ant & is !n read4 ,! pol>ization may be consid]$ z simply r$uc+ ! pot5tial ( ! cell1 & s9ce1 )9 ! range ( conc5trations ( acid us$1--#d-mol> to #a_/h-mol>--! pol>ization curr5t does n v>y m>k$ly1 z comp>$ ) ! pot5tial ( ! /orage cell1 ! total pot5tial us$ ?r\gh ! s]ies ( dilutions may be consid]$ suffici5tly con/ant = ! purposes ( ! exp]im5t4 ,read+s are made ?ree or f\r seconds aft] ea* dilution1 :5 ! pol>ization has be5 fully e/abli%$4 ,pol>ization may be entirely avoid$ by ! use ( a silv] nitrate solution & silv] electrodes or ( a cupric salt solution & copp] electrodes 7,noyes & ,blan*>d74 ,hydro*loric acid is us$ "h 9 ord] to c>ry ! discussion 9 ! text z f> z possible ) ?is typical ionog54 ,if "o takes c>e to make read+s z describ$1 ! result is q satisfactory1 z is %[n by ! comp>ison ( ! ratios ( ! read+s ) ! ratios calculat$ f ! kn[n conductivities ( ! v>i\s dilutions 7see table bel[74 #hj ,curr5t 7,pot5tial ,diff]5ce7 _/ ,resi/ance1 or ,curr5t 7,pot5tial ,diff]5ce7 ,conductivity4 ,= a con/ant pot5tial diff]5ce1 !n1 ,curr5t ,conductivity4 #ha ,! specific conductivity ( a solution 7commonly designat$ by 7 is ! conductivity ( a cube ( #a cm4 edge2 ! molecul> conductivity is ! conductivity ( a mole ( ! electrolyte2 ! equival5t conductivity 7designat$ by 7 is ! conductivity ( a gram-equival5t ( ! electrolyte4 v1 :]e v is ! volume1 express$ 9 cubic c5timet]s1 conta9+ ! gram-equival5t4 ,= in/ance1 ! resi/ance ( #j4a mol> hydro*loric acid 9 a cube ( #a cm4 edge is #bh4e ohms & its conductivity 77 !re=e #a _/ #bh4e or #j4jcea reciprocal ohms4 ,s9ce #aj lit]s or #aj1jjj c4c4 ( #j4a-mol> hydro*loric acid is ! volume 7v7 conta9+ "o mole ( ! acid 7! mol> & ! equival5t conductivities1 = a monobasic acid be+ ! same7 #j4jcea #aj1jjj1 or #cea4 #hb ,kohlraus* & ,holborn1 p4 #bjj4 #hc ,cf4 ,kahl5b]g1 ,transactions ( ! ,f>aday ,society1 #a1 #db 7#aije74 #hd ,clausius1 ,pogg5dorf's ,ann41 #aja1 #cdg 7#aheg7 7,/ud474 ,8 !ory replac$ ! old] "o ( ,grot?uss4 #he ,phil4 ,mag41 #e1 #gbi 7#aijc71 & ,transactions ( ! ,f>aday ,society1 #a1 #ee1 7#aije74 #hf ,vide1 ,hudson1 ,j4 ,am4 ,*em4 ,soc41 #ca1 #aacf 7#aiji71 = a rec5t summ>y ( results4 #hg ,lectures on ,physical ,*emi/ry1 #a1 p4 #aca4 #hh ,vide ,a4 ,a4 ,noyes & ,blan*>d1 ,j4 ,am4 ,*em4 ,soc41 #bb1 #gbf 7#aijj74 #hi ,! conc5trations are figurative1 b may be tak5 to repres5t actual conc5trations1 su* z #j4jae mol>1 etc4 #ij ,kohlraus* & ,holborn1 loc4 cit41 p4 #bjj4 #ia ,ra\lt1 ,ann4 de ,*im4 et de ,phys4 7#f71 #b1 #hd 7#ahhd74 #ib ,! degree ( ionization ( m]curic *loride is bas$ on ,ra\lt's freez+-po9t measurem5ts & is subject to revision1 & ! limit ( ! mobility ( ! m]curic-ion 7 ,hg7 is assum$ to be #dh1 close to ! values f\nd = ! ions ( z9c & cadmium1 elem5ts 9 ! same family z m]cury4 #ic ,lehfeldt's ,electro*emi/ry1 #aijd1 p4 #c4 #id ,see table1 p4 #ef4 #ie ,report ( ! ,briti% ,association = ! ,advancem5t ( ,sci5ce1 #ahhf1 p4 #chi4 #if ,) ! aid ( m elaborate app>atus rigor\s demon/rations & measurem5ts ( su* diffusion curr5ts ( s-call$ conc5tration cells are made4 #ig ,z4 phys4 ,*em41 #fc1 #agd 7#aijh74 ,! "w 0 c>ri$ out 9 ,abegg's laboratory4 #ih ,report ( ! ,/4 ,l\is ,congress ( ,arts & ,sci5ces1 ,,iv1 #cad 7#aijd74 #ii ,am4 ,*em4 ,j41 #bj1 #ba1 #bc 7#ahih-aijj74 #ajj ,kabluk(f1 ,z4 phys4 ,*em41 #d1 #dbi 7#ahhi74 #aja ,phil4 ,mag4 7#e71 #cf1 #cbj 7#ahic74 #ajb ,z4 phys4 ,*em41 #ac1 #eca 7#ahic74 #ajc ,wald51 ,z4 phys4 ,*em41 #ed1 #abi 7#aijf72 ,mc,coy1 ,j4 ,am4 ,*em4 ,soc41 #cj1 #ajgd 7#aijh74 #ajd ,z4 phys4 ,*em41 #ed1 #bbi 7#aijf74 #aje ,! degrees ( ionization 7 always det]m9$ f ! relation v _/ accord+ to ! me?od discuss$ on page #ej4 #ajf ,wald51 loc4 cit4 #ajg ,cf4 ,arrh5ius1 ,!ories ( ,*emi/ry1 p4 #hc 7#aijg74 #ajh ,9 hydrog5 *loride1 ! hydrog5 & ! *lor9e atoms may be held 9 ! molecules ,h,cl by ! electric attraction ( a positive *>ge on ! hydrog51 & a negative *>ge on ! *lor9e atom 7see p4 #dc74 #aji ,frankl9 & ,kraus1 ,am4 ,*em4 ,j41 #bc1 #cje 7#aijj7 7,/ud47 #aaj ,x is v likely t 9 aque\s acids1 a l>ge proportion1 at lea/1 ( ! hydrog5-ion is simil>ly comb9$ ) wat]4 7,lapwor?1 ,j4 ,*em4 ,soc41 7,london7 #ic1 #bahg 7#aijh74 ,see ,*apt] ,,xii47 #aaa ,vide ! discussion on ! ,con/itution ( ,wat]1 & ! summ>y by ,j4 ,walk]1 ,transactions ( ! ,f>aday ,society1 ,,vi1 #ga-abc 7#aiaj74 #aab ,proc4 ,am4 ,acad41 #ahib2 ,liebig's ,ann4 #bhg1 #bfc 7#ahie74 #aac ,cf4 ,wald51 ,z4 phys4 ,*em41 #ee1 #fhc 7#aijf74 p#jfg ,,*apt] ,v ,,! ,,!ory ,,( ,,ionization4 ,,ii ,,ionization ,,& ,,osmotic ,,pressure4 ,,ionization ,,& ,,*emical ,,activity ,we w turn n[ to ! consid]ation ( evid5ce be>+ on ! !ory ( ionization1 f\nd 9 ! data on osmotic pressure4 ,! app>5t molecul> weight ( hydrog5 *loride is f\nd to be small] ?an #cf4e1 :5 det]m9$ 9 aque\s solution 7p4 #cg71 & x is f\nd to approa* ! limit #ah4be z a m & m dilute acid is us$4#aad ,! value f\nd repres5ts ! av]age molecul> weight ( all ! molecules 9 any solution1 ! osmotic pressure1 freez+-po9t or boil+-po9t ( :i* has be5 tak54 ,x is evid5t t1 if !re is dissociation ( hydrog5 *loride into hydrog5 & *loride ions1 ! av]age values f\nd = ! molecul> weight mu/ be l[] ?an #cf4e1 mu/ be v>iable1 & mu/ approa* ! limit #ah4be1 z ! dissociation into ! small] molecules becomes m & m complete4 ,su* a result is1 !re=e1 :at we w\ld anticipate on ! basis ( ! !ory ( ionization4 ,= a salt l potassium *loride ,k,cl1 a simil> t5d5cy t[>d a m9imum1 av]age molecul> weight ( 7,k ,cl7 _/ #b or 7#ci4a #ce4e7 _/ #b #cg4c w\ld be anticipat$1 &1 z a matt] ( fact1 molecul> weight det]m9ations ) potassium *loride 9 aque\s solution give results agree+ ) su* a t5d5cy4#aae ,= a salt l calcium *loride1 on ! o!r h&1 we w\ld expect t its ionization into ?ree ions1 accord+ to ! equation ,ca,cl#b ,ca#b #b ,cl1 w\ld give a m9imum1 n ( "o-half ! =mula weight1 b ( "o-?ird1 viz41 7,ca#b #b ,cl7 _/ #c or 7#dj #ga7 _/ #c #cg1 :5 ! molecul> weight det]m9ation is c>ri$ out 9 aque\s solution4 ,z a matt] ( fact1 ) salts ( ?is type1 ! det]m9ations1 by osmotic pressure me?ods1 indicate a dissociation into ?ree small] compon5ts1 z requir$ by ! !ory4 ,x may be add$ t1 = p#jfh a salt1 sodium mellitate1 ,na#f7;,c#ab,o#ab71 ! salt ( a hexabasic acid1 ,taylor f\nd av]age molecul> weights t5d+ to a m9imum ( "o-sev5? ( ! =mula weight1 z we %\ld expect f ! ionization ( ! salt into sev5 small] molecules1 7,c#ab,o#ab7,na#f #f ,na 7,c#ab,o#ab7f4 ,quantitative ,evid5ce4--,"s ( ! mo/ exact quantitative evid5ce be>+ on ^! relations1 su* z ! results ( inve/igations1 by ,griffi? & by ,taylor1 on ! freez+-po9t depressions ( solutions ( electrolytes1 may be briefly consid]$4 ,! depression ( ! freez+-po9t ( a giv5 solv5t by a solute is proportional to ! conc5tration ( ! solute or proportional to its osmotic pressure4 ,fur!r1 accord+ to ! ,van 't ,h(f ,hypo!sis 7p4 #ae71 ! osmotic pressure at a con/ant temp]ature is dep5d5t only on ! numb] ( molecules pres5t 9 unit volume1 & n on ! nature or composition ( ! molecules3 ! freez+-po9t ( ! solv5t is depress$1 likewise1 proportionally to ! total conc5tration ( ! solute1 irrespective ( ! fact :e!r ! solution conta9s only "o1 or m ?an "o molecul> species4 ,! ratio1 obs]v$ depression _/ conc5tration1#aaf or _/ ,c1 %\ld be con/ant1#aag !re=e1 9 a giv5 solv5t1 = dilute solutions ( all k9ds ( solutes1 simple or mix$4 ,griffi?#aah f\nd1 = a solution ( cane sug>1 a non-electrolyte1 9 wat]1 ! ratio ( ! freez+-po9t depression to ! conc5tration to be #a4heh4 ,= in/ance1 ! freez+-po9t ( a #j4ja mol> solution ( cane sug> 7#c4db grams ( cane sug> p] lit]2 ,c#ab;,h#bb,o#aa #cdb7 is f\nd to be #j4jaheh1 & #j4jaheh _/ #j4ja #a4heh4 ,?is ratio %\ld be ! same1 z /at$ above1 accord+ to van 't ,h(f's !ory ( solutions1 = dilute aque\s solutions ( all solutes4 ,b ! ratio _/ ,c = an aque\s solution ( potassium *loride1 an electrolyte1 0 f\nd to increase sl[ly & cont9u\sly until 9 #j4jjjc mol> solution ! ratio #c4gb 0 f\nd1 :i* is exactly twice ! value obta9$ ) cane sug>4 ,! result indicates1 !re=e1 a gradual dissociation ( ! potassium *loride ) increas+ dilution1 & a dissociation1 ultimately1 ( ea* molecule ( ! salt into two new molecules1 9 all respects exactly z dem&$ by ! !ory ( ,arrh5ius4 ,loomis#aai f\nd 9 a simil> way a ratio ( #c4fa = ,h,cl1 #c4ga p#jfi = ,,koh1 #c4fj = ,k,cl1 #c4fg = ,na,cl1 #c4gc = ,,hno#c1 etc41 :5 #j4ja mol> aque\s solutions 7 us$4 ,= simil> solutions ( calcium *loride ,ca,cl#b1 magnesium *loride ,mg,cl#b1 & sodium sulphate ,na#b,,s#d1 ! value #e4jg 0 f\nd z ! ratio betwe5 ! depressions ( ! freez+-po9t & ! conc5tration ( ! salts 9 extremely dilute solutions--a result %[+1 pla9ly1 a dissociation ( ea* salt into ?ree small] molecules4 ,! limit #e4fg = su* a dissociation is n q rea*$ 9 ^! cases1 because salts ( ! types ,me,x#b & ,me#b,y ionize less readily ?an d ! electrolytes ,me,x1 a fact also %[n by _! conductivities4 ,we ?us f9d t ! mo/ exact "w on molecul> weight det]m9ations 9 dilute aque\s solutions agrees excell5tly1 z does ! conductivity ( su* solutions1 ) ! dem&s ( ! !ory ( ionization1 a fact :i* is p>ticul>ly impressive because osmotic pressure & electrical conductivity are 9 no wise fundam5tally relat$ ph5om5a1 & yet ea*1 z a measure ( ionization or electrolytic dissociation1 leads indep5d5tly to ! same conclusion4#abj ,! ,*emical ,composition ( ! ,ions ( ,electrolytes4--,accept+ ! !ory ( ,arrh5ius1 we may n[ inquire m closely ?an h]et(ore1 fir/1 :at comp\nds are subject to electrolytic dissociation1 & !n1 :at ! *emical composition ( _! ions is & h[ x is det]m9$4 ,! comp\nds :i* are dissociat$ into ions1 by solv5ts :i* cause ionization 7p4 #fb71 comprise ! salts1 ! acids & ! bases2 *emi/s are1 9 fact1 m incl9$ n[ to inv]t ! /atem5t & say t ^? sub/ances :i* h long be5 kn[n z salts1 acids & bases1 owe ! ess5tial *>act]i/ics1 :i* l$ to _! classification1 to ! fact t !y are ionizable 7see pp4 #gb-hb74 ,! composition ( ! ions1 =m$ f ! simpl] ( ^! comp\nds1#aba may be express$ by say+ t ! metal compon5t or metal-l compon5t 7hydrog51 ammonium7 =ms ! positive ion 7cation1 metal ion7 & all ! re/ ( ! p#jgj molecule =ms ! negative ion 7anion1 acid ion#abb74 ,?us1 sodium *loride1 nitrate1 sulphate1 phosphate yield ! sodium-ion1 ,na1 & ! *loride 7,cl71 nitrate 7,,no#c71 sulphate 7,,s#db71 or phosphate 7,,po#dc7 ions2 cupric nitrate ,cu7,,no#c7b dissociates into ! cupric ion 7,cu#b7 & ! nitrate ion1 calcium sulphate ,ca,s,o#d into ! calcium-ion 7,ca#b7 & ! sulphate-ion1 alum9ium sulphate ,al#b7,,s#d7c into ! alum9ium-ion 7,al#c7 & ! sulphate-ion4 ,b ! "q arises1 z to h[ we "k t ! salts m5tion$ produce ions ( ! giv5 composition2 :y1 = in/ance1 %\ld sodium nitrate be consid]$ to dissociate into sodium1 ,na1 & nitrate ions1 ,,no#c1 ! nitrog5 atom c>ry+ all ( ! oxyg5 atoms ) x 9 ! negative ion8 ,illu/ration3 ,,fig4 #ac4 ,! composition ( ! ions ( a salt c be det]m9$ exp]im5tally#abc by devices ( :i* ! ,u-tube exp]im5t 7p4 #de7 may be consid]$ to be a simple type4 ,= in/ance1 if we wi% to det]m9e ! composition ( ! ions ( sodium nitrate1 we c\ld cov] a solution ( sodium nitrate ) a solution1 say1 ( hydro*loric acid1 pass a curr5t ?r\gh ! liquids1 & det]m9e ! composition ( ! compon5ts t h mov$ to ! negative & positive poles1 respectively4 ,9 practice1 ! device c\ld be elaborat$ = ! sake ( conv5i5ce4 ,/opcocks1 = in/ance1 might be plac$ 9 ! ,u-tube1 at ! po9ts ( sep>ation ( ! nitrate solution & ! hydro*loric acid 7see ,fig4 #ac71 ! /opcocks be+ op5$ only dur+ ! passage ( ! curr5t4 ,or por\s plates or cells might be us$1 9 place ( /opcocks1 at ^! p#jga po9ts4 ,n[1 if we assume sodium nitrate to be dissociat$1 n into ,na & ,,no#c1 b let u say into positive ions ,na,o & negative ions ,,no#b1 ! *anges :i* w\ld result f ! passage ( a curr5t w\ld be z foll[s3 />t+ ) ! action at ! positive pole1 we %\ld f9d *loride ions dis*>g$ & *lor9e evolv$ at ! pole 7! evolution ( *lor9e c\ld be avoid$1 if consid]$ desirable1 by ! use ( a silv] anode1 :i* w\ld absorb ! lib]at$ *loride-ion to =m insoluble silv] *loride on ! electrode74 ,at ! same "t1 hydrog5 ions w\ld move out ( ! space ,p1 be+ repell$ by ! positive pole1 & attract$ by ! negative4 ,at ! b\nd>y betwe5 ! sodium nitrate solution & ! hydro*loric acid1 ! negative ions ( sodium nitrate1 :i* we are suppos+ to h ! composition ,,no#b1 w\ld move up f ,b t[>d ! positive pole 7cf4 exp41 p4 #de71 be+ attract$ by its *>ge2 at any mom5t we %\ld h 9 any "p ( ,p z _m negative ions 7,cl & ,,no#b71 z !re are hydrog5 ions1 ! solution %[+ no excess ( free electricity at any po9t4 ,n[1 if ,,no#b 7 ! ion t mov$ up into ! space ,p1 !n we %\ld pres5tly f9d nitr\s acid ar\nd ! positive pole 9 space ,p1 ,h & ,,no#b comb9+ to =m nitr\s acid1 ,,hno#b4 ,b1 z a matt] ( exp]im5t1 al?\gh ! te/s = nitr\s acid belong to ! mo/ s5sitive ones 9 *emi/ry1 no trace ( ?is acid is f\nd !re2 :at we d f9d is nitric acid1 ,,hno#c1 result+ obvi\sly f ! pres5ce 9 space ,p ( bo? hydrog5 ions & nitrate ions1 ,,no#c1 :i* h mov$ up f space ,b4 ,x is cle>1 t ! pres5ce ( nitric acid 9 ! region ar\nd ! positive pole means t ! nitrog5 atoms mu/ h c>ri$ ) !m all ?ree ( ! oxyg5 atoms ( ! nitrate--9 a ^w1 t ! composition ( ! negative ion ( sodium nitrate is ,,no#c & n1 say1 ,,no#b4 ,simil>ly1 consid]+ :at happ5s 9 space ,n1 r\nd ! negative pole1 we h "h an evolution ( hydrog51 a migration ( "s *loride ions out ( ,n into ! space ,c1 &1 at ! same "t1 a migration ( ! positive ions ( space ,c into ! division ,n4 ,on exam9+ ! solution 9 ,n1 we n[ f9d sodium *loride1 ) un*ang$ hydro*loric acid1 exactly :at we %\ld expect f ! migration ( ! ion ,na t[>d ! negative electrode4#abd ,if ! positive ion 71 say1 p#jgb ,na,o1 we %\ld expect to obta9 ei!r "s ( ! hypo*lorite ,na,o,cl 7,na,o ,cl71 or1 at lea/1 an evolution ( oxyg5 9 ?is place1 s9ce sodium *loride is =m$4 ,z a matt] ( exp]im5t1 no oxyg5 is evolv$ "h1 & no trace ( hypo*lorite is f\nd 9 ,n r\nd ! negative pole1 al?\gh ! te/s = hypo*lorites are extremely s5sitive4 ,comp>atively simple me?ods1 9 pr9ciple ( ! nature outl9$1 enable u1 !n1 to det]m9e exp]im5tally ! composition ( ! ions into :i* ionizable comp\nds1 salts1 acids & bases1 dissociate4 ,:5ev] any d\bt may exi/ ab\t ! composition ( ! ions ( a giv5 electrolyte1 ?is device may be employ$ to settle ! matt]1 & !re w pres5tly be occasion to employ ! ,u-tube = su* a purpose4 ,ionization & ,*emical ,activity4--,! fact t ! !ory ( ionization gives u adequate explanations ( ! conductivity %[n by dissolv$ electrolytes & ( _! abnormally high osmotic pressures1 w\ld h be5 9 itself ( int]e/ to *emi/s2 b1 if its applications 7 limit$ to ^! ph5om5a1 we %\ld n be consid]+ x 9 connection ) qualitative *emical analysis1 nor w\ld ! !ory1 presumably1 h greatly affect$ ! developm5t ( *emi/ry1 z x has done4 ,x is ! fact t ! electrolytic dissociation ( an electrolyte into its ions involves *emical *anges ( ! mo/ pr(\nd nature1 & mo/ intimately affects *emical reactivity1 t has made x play1 9 ! la/ two decades1 su* a lead+ rle 9 ! developm5t ( *emi/ry1 & t makes x necess>y to include its consequ5ces 9 ! consid]ation ( analytical problems1 if "o w\ld und]/&1 z f> z pres5t k p]mits1 ! reactions involv$ 9 *emical analysis4 ,hydrog5 *loride1 z a p]fectly dry gas1 is a non-conductor ( electricity &1 at ! same "t1 x is f\nd to be *emically inactive--x does n comb9e1 = in/ance1 ) dry ammonia#abe or act ^u dry calcium c>bonate#abf or on dry litmus4 ,hydrog5 *loride1 subject$ to great pressure at a l[ temp]ature1 is liquefi$4 ,! liquid is also a v poor conductor ( p#jgc electricity#abg & does n %[ ! *emical activity ( ord9>y1 aque\s hydro*loric acid2 x does n comb9e ) calcium oxide or attack m>ble1 z9c1 iron or ev5 magnesium4#abg ,a solution ( hydrog5 *loride 9 a poorly ioniz+ m$ium1 l b5z5e or tolu5e1 is an extremely poor conductor4 ,!re is an extremely small conductivity indicat+ only a trace ( ionization4#abh ,,exp4 ,a solution ( hydrog5 *loride1 prep>$ by pass+ ! dri$ gas into b5z5e or tolu5e 7?ioph5e-free b5z5e w n become discolor$71 & kept anhydr\s by means ( fus$ calcium *loride1 is te/$ = its conductivity1 by dipp+ into x electrodes connect$ ) a light+ circuit & a galvanomet]4 ,su* a solution behaves *emically1 also1 q diff]5tly f ! aque\s solutions ( hydrog5 *loride ) :i* we are famili>3 dry /eel nails1#abi dropp$ into x1 w rema9 almo/ un*ang$--!re is no m>k$ evolution ( hydrog5 7exp474 ,p]fectly dri$ m>ble1 add$ to x1 w n give rise to ! evolution ( c>bon dioxide#abi 7exp474 ,we f9d ?us1 9 all ! cases discuss$--! nonconduct+ dry gas1 ! anhydr\s liquefi$ hydrog5 *loride & ! anhydr\s b5z5e solution--an abs5ce ( ionization1#acj z indicat$ by ! lack ( conductivity1 &1 along ) ?is1 a lack ( ! famili> action ( hydro*loric acid z an acid4 ,if we dissolve ! gas 9 wat]1 we obta9 a well-conduct+ solution 7exp471 9 :i*1 accord+ to molecul> weight det]m9ations1 ! p#jgd hydrog5 *loride is m or less l>gely ioniz$1 & ?is same solution has all ! well-kn[n *emical prop]ties ( hydro*loric acid--x evolves hydrog5 lib]ally :5 giv5 an opportunity to act ^u z9c or iron 7exp471 x evolves c>bon dioxide copi\sly :5 m>ble is br\ght into contact ) x 7exp474 ,9 su* an aque\s solution we h bo? ! ions ( ! acid & ! m or less non-ioniz$ hydrog5 *loride1 ! action 7,h,cl ,h ,cl7 be+ rev]sible4 ,n[1 s9ce 9 ^? cases 9 :i* we h admitt$ly only non-ioniz$ hydrog5 *loride1 !re is no vigor\s *emical action1 we are b\nd to conclude t1 9 ! aque\s solution :]e we h bo? ! non-ioniz$ & ! ioniz$ sub/ance1 x mu/ be ! new compon5ts1 ! ions ( ! acid1 :i* give ?is solution its new qualities1 ! well-kn[n prop]ties ( a pron\nc$ acid4#aca ,?is conclusion1 t ! acid prop]ties ( hydrog5 *loride 9 aque\s solution are due to ! ioniz$ hydrog5 *loride1 r ?an to ! hydrog5 *loride itself1 is "o ( fundam5tal importance4 ,dry ,salts & _! ,aque\s ,solutions4--,if ! /udy ( ! relation ( ionization to *emical activity be ext5d$1 x is f\nd t a dry salt1 su* z1 = example1 silv] nitrate1 9 cry/als or f9ely pulv]iz$1 is n p]ceptibly ioniz$1 = x is a non-conductor 7exp474 ,! same result is obta9$ ) potassium *romate4 ,if ! dry p[d]s are intimately mix$1 !re is no *emical action betwe5 !m1 no p]ceptible *ange occurs4 ,! aque\s solutions ( ! salts are excell5t conductors 7exp471 z are ! aque\s solutions ( almo/ all salts2 ! dissolv$ salts are !re=e l>gely ioniz$4 ,z soon z ! ioniz+ m$ium1 wat]1 is add$ to ! dry1 yell[ mixture ( silv] nitrate & potassium *romate1 in/antly a *emical *ange results--r$ silv] *romate1 ,ag#b;,cr,o#d1 is precipitat$ 7exp474 ,n[1 9 ! aque\s solution ( ^! salts we h bo? non-ioniz$ molecules & _! ions3 ,ag,n,o#c ,ag ,,no#c1 ,k#b;,cr,o#d #b ,k ,cr,o#db4 ,s9ce !re is no int]action :5 ! dry salts1 conta9+ only ! non-ioniz$ sub/ances1 are mix$1 & s9ce !re is int]action p#jge :5 ! solutions are mix$1 9 :i* bo? ! non-ioniz$ & ! ioniz$ salts are pres5t1 "o mu/ conclude aga9 t ! =mation ( silv] *romate is ! result ( ! action ( ! silv] ions on ! *romate ions 9 ! solution4 ,9 po9t ( fact1 !re c\ld h>dly fail to be an action1 s9ce ! positive silv] ions & ! negative *romate ions1 mov+ 9 all directions ?r\gh ! solution1 mu/ collide & be dis*>g$1 or comb9e1 to =m molecul> silv] *romate4 ,?is salt happ5s to be v difficultly soluble1 & to be color$ r$1 z well1 s t silv] *romate is precipitat$ & is imm$iately recognizable4 ,! two dry p[d]s 9 ! exp]im5t 7 all[$ to be 9 contact = only a few mom5ts4 ,x is important to note1 !re=e1 t dry sodium acid c>bonate & dry potassium acid t>trate are also nonconductors 7exp471 & t ! intimate mixture ( ^! two p[d]s is kept = ye>s 9 ! well-kn[n =m ( bak+ p[d]s )\t appreciable decomposition--yet be/ 9 t9 vessels1 to exclude moi/ure4 ,! aque\s solutions1 h[ev]1 are good conductors 7exp471 &1 :5 dissolv$1 ^! salts are m or less ioniz$4 ,! addition ( wat] to ! mix$ salts 7exp47 leads at once to ! well-kn[n action1 c>bon dioxide be+ lib]at$ & sodium-potassium t>trate or ,ro*elle salt be+ =m$4 ,behavior ( ,fus$ ,salts4--,x may be object$ t !re are common cases1 :]e dry salts are kn[n to act ^u ea* o!r2 b>ium sulphate is fus$ ) sodium c>bonate to conv]t ! =m] into ! c>bonate1 ,ba,s,o#d ,na#b;,,co#c ,na#b,,s#d ,ba,c,o#c4 ,be=e "o decides t ?is mu/ be an in/ance ( ! action ( non-ioniz$ salts on ea* o!r1 ! conductivity ( dry salts "u ! conditions ( ! exp]im5t1 namely at an elevat$ temp]ature1 mu/ be exam9$4 ,!re is no difficulty 9 recogniz+ t :ile dry sodium c>bonate or potassium nitrate at ord9>y temp]atures does n conduct a curr5t1 & is n p]ceptibly ioniz$1 ea* salt1 :5 fus$1 becomes an excell5t conductor 7exp41#acb ) potassium nitrate74 ,x is1 9 fact1 well kn[n t1 9 _m electrolytic op]ations1 fus$ salts#acc are us$ 9 place p#jgf ( solutions4 ,x mu/ be add$ t ! heat1 n ! *ange ( /ate1 causes ! ionization1 c>eful "w hav+ %[n t conductivity beg9s to be appreciable bel[ ! po9t ( fusion4 ,,exp4 ,two plat9um wires1 fus$1 "o in* ap>t1 into a glass rod1 are connect$ ) a s5sitive galvanomet] & ! light+ circuit4 ,:5 ! glass is w>m$1 a curr5t is f\nd to pass4 ,! action betwe5 b>ium sulphate & sodium c>bonate at a high temp]ature does n mean1 !n1 t ! non-ioniz$ salts int]act2 on ! contr>y1 we f9d t1 "u su* conditions1 co9cid5t ) ! evid5ce ( reactivity1 we h also decid$ conductivity--aga9 indicat+ decid$ ionization4 ,dry ,salts at ,ord9>y ,temp]atures4--,inasmu* z ord9>y temp]atures are /ill f> remov$ f ! absolute z]o1 "o mu/ suppose t dry salts mu/ be ioniz$1 m9imally at lea/1 ev5 at room temp]ature1 & %\ld !re=e react ) ea* o!r4 ,presumably !y d1 only s sl[ly1 z a result ( ! m9imal degrees ( ionization1 & ( ! few *ances ( collision betwe5 ions ( opposite *>ges1 ow+ to ! re/rict$ range ( ! molecul> motions1 t ! total *ange is imp]ceptible4 ,critical "w on ! "q is mo/ desirable4 ,9 ?is connection x maybe said t ,spr+#acd f\nd t dry salts d int]act at ord9>y temp]ature1 :5 subject$ to great pressures1 provid$ ! volume ( ! products is small] ?an ! volume ( ! initial sub/ances4 ,:e!r ?is action is due to ! ionization ( ! salts1 m9imal z x is1 or :e!r we h "h a case ( int]action ( non-ioniz$ molecules1 has n1 x seems1 be5 det]m9$2 x w\ld require difficult quantitative "w to settle ! "q4 ,influ5ce ( ,light & ,heat4--,x is app>5t t heat1 a =m ( en]gy1 contributes to ! dissociation ( ionog5s1 & x is natural t we %\ld consid] o!r =ms ( en]gy1 e4g4 light1 to h ! same p[]4 ,"o may speculate ab\t ! possibility ( light induc+ *emical action 7e4g4 9 />t+ ! comb9ation ( hydrog5 & *lor9e1 or 9 photography7 by its ioniz+ p[]1 & ab\t ! possibility t rapid comb9ation ( oxyg5 & hydrog5 foll[s ! application ( a flame to ! mixture1 z ! result ( increas$ ionization ( ! compon5ts at ! elevat$ temp]ature ( ! flame & ( ! burn+ gases4 ,! exp]im5tal evid5ce %[s t1 9 "s actions ( ?is nature1 ionization is an important factor1 :ile 9 o!r in/ances x appe>s to be negligible4#ace p#jgg ,conclusions4--,x appe>s t we mu/ accept ! conclusion1 t ! reactions ( salts1 acids & bases 7ionog5s7 9 aque\s solution 7! s-call$ salt reactions7 are ! reactions ( ! ions & n ( ! non-ioniz$ molecules4 ,?is conclusion is ( ! greate/ & mo/ practical importance 9 our sci5ce4 ,x is ! natural inf]5ce f ! results ( ! qualitative exp]im5ts describ$ 9 ! ?ree prec$+ sections4 ,its f9al adoption1 h[ev]1 is bas$ on ! exi/5ce ( a great mass ( quantitative evid5ce1 & to ! consid]ation ( "s ( ?is we n[ turn4 ,quantitative ,relations4--,if ! active compon5ts 9 aque\s solutions ( acids1 bases & salts are ! ions1 r ?an ! undissociat$ comp\nds1 !n quantitative data support+ su* a conclusion %\ld be f\nd4 ,su* quantitative confirmation1 f ! po9t ( view ( *emical activity1 is n lack+4 ,only a small "p ( ! data c be consid]$ "h4 ,conductivity measurem5ts1 & ! l[]+ ( freez+-po9ts & ! elevation ( boil+-po9ts1 %[ t !re are v decid$ diff]5ces 9 ! degrees ( ionization ( diff]5t acids & bases 9 solutions ( equival5t conc5tration4 ,= in/ance1 potassium hydroxide is some:at m ioniz$ ?an is b>ium hydroxide1 & decid$ly m s ?an ammonium hydroxide1 a fact t c readily be demon/rat$ by ! conductivities ( ! solutions#acf3 ,,exp4 ,equival5t solutions 7#a _/ #aj normal7 ( ! ?ree bases are introduc$ into ?ree v]tical tubes1 conta9+ electrodes connect$1 9 p>allel1 ) a light+ circuit & ) small electric lamps4 ,:5 ! two electrodes 9 ea* ( ! ?ree tubes are at equal di/ances f ea* o!r1 ! lamp connect$ ) ! potassium hydroxide solution gl[s mo/ brightly1 t connect$ ) ! b>ium hydroxide solution a little less brightly1 & ! lamp connect$ ) ! ammonium hydroxide solution does n gl[ at all--n en\gh curr5t is c>ri$ ?r\gh ! ammonium hydroxide solution to heat ! filam5t 9 ! correspond+ lamp suffici5tly to make x r$4 ,n[1 ! curr5t1 = a giv5 fall ( pot5tial1 is proportional to ! conductivity ( a solution 7p4 #dh7 &1 9 ! equival5t solutions#acg ! conductivity dep5ds on ! proportion ( *>g$ p>ticles 7! degree ( ionization7 ( ! base4 ,x is cle> !n1 t ammonium hydroxide is v mu* less ioniz$ ?an are ! two o!r bases4 p#jgh ,! resi/ance 9 a tube may be r$uc$1 & ! conductivity increas$1 by r$uc+ ! di/ance ?r\gh :i* ! curr5t mu/ be c>ri$1 i4e4 by br++ ! electrodes clos] toge!r4 ,9 ! solution ( b>ium hydroxide1 we f9d t we mu/ r$uce ! di/ance betwe5 ! electrodes to ab\t five-six?s ! correspond+ di/ance 9 ! potassium hydroxide solution be=e we obta91 approximately1 z bright a lamp f ! curr5t pass+ ?r\gh x1 & 9 ! case ( ammonium hydroxide1 we mu/ br+ ! electrodes s close toge!r t !y almo/ t\*1 ! di/ance be+ only "o or two hundr$?s ( ! di/ance betwe5 ! electrodes 9 ! potassium hydroxide solution4 ,= ! degrees ( ionization ( ! ?ree bases we h1 approximately1 ! relation ,k 3 ,ba 3 ,,nh#d33 d,k 3 d,ba 3 d,,nh#d1 if we indicate by d,k1 d,ba1 d,,nh#d ! di/ances betwe5 ! electrodes 9 ! ?ree solutions :5 ! lamps are ( uni=m brightness1 i4e4 :5 ! same quantity ( curr5t passes ?r\gh ea* solution4 ,9 ?is d$uction1 ! conductivities ( ! bases at inf9ite dilution 77 are tak5 to be ! same1 :i* is r\ghly true4 ,! exp]im5t gives u a r\gh measure ( ! relative conductivities & ! relative degrees ( ionization ( ! ?ree bases4 ,x %[s t potassium hydroxide is some:at m ioniz$ ?an is b>ium hydroxide1 9 equival5t solution1 & decid$ly m ?an is ammonium hydroxide4 ,limit+ ! fur!r discussion1 at ?is mom5t1 to potassium hydroxide & ammonium hydroxide1 we %\ld f9d t1 s9ce 9 equimol> solutions1 a l>g] portion ( ! =m] is ioniz$ ?an ( ! latt]1 ! potassium hydroxide solution mu/ conta9 ! l>g] proportion or conc5tration ( hydroxide-ion1 ,,ho1 :i* is ! *>act]i/ic ion ( bases4 ,x %\ld1 !re=e1 %[ ! *emical *>act]i/ics ( a base mu* m decid$ly ?an ! ammonium hydroxide solution4 ,t su* is ! case c be v simply %[n by add+ equal quantities 7#j4a c4c47 ( ! #j4a mol> solutions to equal volumes 7#ej c4c47 ( wat]#ach conta9+ "s ph5olph?alen4 ,?is is an indicator = bases & acids1 l litmus1 b x is less s5sitive to hydroxide-ion ?an is litmus4 ,we f9d t ! potassium hydroxide causes a v decid$ *ange1 produc+ a deep r$ color ) ! ph5olph?alen1 :]eas ! ammonium hydroxide only produces a p9k hue4#aci p#jgi ,9 all ! *emical *anges produc$ by ^! alkalies1 ! same diff]5ce 9 int5sity ( action is %[n1 t is "h exhibit$ t[>ds indicators4 ,if1 = example1 we measure ! rate ( *ange 9 an action1 :i* is sl[ en\gh to be measur$ & :i* proce$s quantitatively 9 proportion to ! conc5tration ( hydroxide-ion1 we f9d t ! measur$ rates ( *ange indicate ! same ratio 9 ! conc5trations ( hydroxide-ion 9 potassium & ammonium hydroxide solutions1 z is indicat$ by quantitative conductivity measurem5ts4 ,an action suitable = ! purpose is ! saponification ( an e/]1 su* z e?yl acetate4 ,"u ! influ5ce ( an alkali1 l potassium hydroxide1 e?yl acetate is decompos$1 m or less rapidly1 into an acetate & alcohol3 we h1 = in/ance1 ,,*#c;,,co#b;,c#b;,h#e ,,koh ,,*#c;,,co#b,k ,c#b;,h#e,,oh4 ,! rate ( saponification is f\nd to be proportional to ! conc5tration ( hydroxide-ion1 & n to ! total conc5tration ( ! base1 & ! action may be =mulat$ m accurately z foll[s3 ,,*#c;,,co#b;,c#b;,h#e ,k ,,ho ,,*#c;,,co#b ,k ,c#b;,h#e,,oh or ,,*#c;,,co#b;,c#b;,h#e ,,ho ,,*#c;,,co#b ,c#b;,h#e,,oh4 ,= ammonium hydroxide we h simil>ly1 ,,*#c;,,co#b;,c#b;,h#e ,,nh#d ,,ho ,,*#c;,,co#b ,,nh#d ,c#b;,h#e,,oh4 ,n[1 ,arrh5ius#adj prov$ t ! rate ( saponification ( e?yl acetate by ammonium hydroxide1 :i* is v mu* sl[] ?an ! rate ( saponification by potassium hydroxide ( equival5t conc5tration1 does agree quantitatively1 inde$1 ) ! rate dem&$ by ! !ory ( ionization1 :5 ! hydroxide-ion is consid]$ ! active compon5t ( ! bases1 to :i* ! saponification is due4 ,,exp4 ,a r\gh idea ( ! diff]5ce 9 ! *emical actions ( ! two bases may be obta9$ by obs]v+ _! effects on ! e/]1 me?yl acetate1 :i* is decompos$ into an acetate & me?yl alcohol r rapidly4 ,to #ej c4c4 ( 7,,co#b free7 wat] conta9+ "s ph5olph?alen1 #aj c4c4 ( #j4a mol> potassium hydroxide is add$2 a simil> mixture ) #aj c4c4 ( #j4a mol> ammonium hydroxide solution is prep>$4 ,to ea* ( ! solutions1 #b c4c4 7an excess7 ( me?yl acetate is add$ 7to ! ammonium hydroxide solution fir/71 & ! mixtures are %ak5 = a mom5t4 ,at room temp]ature1 ! mixture conta9+ potassium hydroxide w become pale p9k 9 a few m9utes1 & colorless soon !reaft]1 :ile ! mixture p#jha conta9+ ammonium hydroxide w /ill be deep r$ at ! end ( #de m9utes4#ada ,9 ! foll[+ tables are summ>iz$ "s ( ! results :i* h be5 obta9$ 9 comp>+ ! activity ( bases1 9 saponify+ me?yl acetate1 & ! conc5trations ( ! hydroxide-ion1 9 ! solutions ( ! bases1 z det]m9$ by conductivity measurem5ts4 ,! comp>isons are made by repres5t+ ! activity ( ! hydroxide-ion 9 a solution ( li?ium hydroxide by #ajj & by express+ ! ratio ( ! activity ( a giv5 base to t ( ! li?ium hydroxide 9 p]c5tages ( ! activity ( ! latt]4 ,all ! bases 7 us$ 9 #j4jbe mol> conc5tration1 & _! degrees ( ionization are giv5 9 ! la/ column ( ! table4 ,,*emical ,,activity ,,( ,,bases ,,& ,,_! ,,ionization,a ,relative ,base4 ,activity4 ,conc5tration ( ,,ho4 ,li?ium hydroxide #ajj #ig ,potassium hydroxide #ih #ig ,sodium hydroxide #ih #ig ,ammonium hydroxide #b #b4e ,e?yl ammonium hydroxide #ab #af4 ,,table ,,note3 ,a4 ,:e?am1 ,!ory ( ,solutions1 p4 #cch 7#aijb74 7,cf4 ,walk]1 ,introduction to ,physical ,*emi/ry1 p4 #bgg 7#ahii747 ,an e/] is decompos$ also "u ! influ5ce ( acids1 9 aque\s solution1 into an organic acid & an alcohol1 & cane sug> is simil>ly decompos$ into glucose & fructose 7grape sug> & fruit sug>73 ,c#ab;,h#bb,o#aa ,h#b,o ,c#f;,h#ab,o#f ,c#f;,h#ab,o#f4 ,bo? actions are f\nd to be caus$ by ! influ5ce ( ! hydrog5 ions ( ! acids us$ & to proce$1 at a giv5 temp]ature1 ) a velocity proportional to ! conc5tration ( ! hydrog5 ions4 ,n[1 9 #j4a mol> solution1 acetic acid is v little ioniz$ 7#a4c71 z comp>$ ) hydro*loric acid 7#ia71 ! degrees ( ionization be+ det]m9$ by conductivity measurem5ts 7p4 #ej72 ! relation may easily be demon/rat$ ) ! aid ( ! conductivity app>atus us$ to %[ ! diff]5ce 9 ionization betwe5 potassium hydroxide & ammonium hydroxide4 ,9 ! pres5ce ( #j4a mol> hydro*loric acid1 ! decomposition ( cane sug> actually proce$s at #gi times ! rate t x does 9 ! pres5ce ( #j4a mol> acetic acid4 ,! ratio ( ! conc5trations ( ! hydrog5-ion 9 ! two p#jhb solutions is1 9 fact1 #gj 3 #a4 ,!re is1 !re=e1 close agreem5t#adb betwe5 ! relative *emical activity ( ! two acids & ! relation dem&$1 if we assume1 on ! basis ( ! !ory ( ionization 7p4 #gg71 t ! *emically active compon5ts ( ! acids are _! ions & p>ticul>ly _! hydrog5 ions4 ,9 ! foll[+ table1 ! relative activities ( acids1 9 accel]at+ ! decomposition ( me?yl acetate by wat]1 are contra/$1 9 a simil> fa%ion1 ) _! relative conductivities4 ,! conductivities ( acids dep5d to su* an ext5t on ! conc5tration ( hydrog5-ion1 :i* moves five times1 or m1 fa/] ?an ! anions & c>ries !re=e ! great] "p ( ! curr5t1 t ! conductivities ( acids1 9 equival5t conc5trations1 may be consid]$ an approximate measure ( _! relative degrees ( ionization & ( ! conc5trations ( hydrog5-ion4 ,= ! purpose ( comp>ison ! activity & ! conductivity ( mol> hydro*loric acid are bo? repres5t$ by #ajj4 ,all ! acids 7 us$ 9 normal solutions4 ,,*emical ,,activity ,,( ,,acids ,,& ,,_! ,,ionization4,a ,acid4 ,activity4 ,conductivity4 ,hydro*loric acid #ajj #ajj ,nitric acid #ib #ajj ,sulphuric acid #gd #fe ,acetic acid #j4c #j4d ,=mic acid #a4c #a4g ,*loracetic acid #d4c #d4i ,t>t>ic acid #b4c #b4c ,,table ,,note3 ,a4 ,:e?am1 ,!ory ( ,solutions1 p4 #cch4 ,9 ! foll[+ *apt]s &1 inde$1 ?r\gh\t our fur!r "w1 we %all cont9ually meet additional in/ances ( ! quantitative relation betwe5 *emical activity & ionization4 ,9 fact1 ! results obta9$ 9 ! field ( quantitative measurem5t ( *emical action1 ( :i* ! above are s+le in/ances1 h demon/rat$1 m ?an any?+ else1 ! value ( ! !ory ( ionization to *emi/ry & ! necessity ( tak+ x into acc\nt 9 express+ ! results ( *emical action 9 ma!matical t]ms4 p#jhc ,summ>y4--,measurem5ts made1 !n1 9 ?ree great & indep5d5t fields ( inve/igation1 electrical conductivity1 osmotic pressure & ! alli$ relations1 & *emical activity1 br+ indep5d5t te/imony to ! correctness ( ! fundam5tal assumptions ( ,arrh5ius's !ory ( ionization4 ,9 ! quantitative /udy ( solutions ( electrolytes1 :]ev] second>y di/urb+ influ5ces are elim9at$ or are tak5 into acc\nt z f> z possible1 ! ?ree l9es ( inve/igation give results :i* agree satisfactorily#adc z to ! degree ( ionization ( ! electrolytes "u exam9ation4 ,) ! aid ( ?is !ory1 pr$ictions ( ! c\rse ( *emical action may n[ be made m def9itely & ) m assurance ?an ev] be=e 9 ! hi/ory ( *emi/ry4 ,*emical ,activity ( ,non-ioniz$ ,molecules4--,! conclusion rea*$1 on ! basis bo? ( qualitative &1 p>ticul>ly1 ( quantitative evid5ce1 t ! reactions ( salts1 acids & bases 7ionog5s7 9 aque\s solutions 7! s-call$ salt reactions7 are ! actions ( ! ions & n ( ! non-ioniz$ molecules1 does n necess>ily mean t ! non-ioniz$ molecules are altoge!r inactive *emically4 ,"s *emi/s believe t ions h only ! advantage ( an enorm\sly great] degree ( reactivity4#add ,if ! atoms 9 a molecule c>ry electric *>ges ev5 prior to _! sep>ation 7ionization71 z express$ = in/ance by ! =mula ,h,cl = hydrog5 *loride 7p4 #dc71 x c be readily se5 t an action#ade result+ f ! collision ( a molecule ( hydrog5 *loride ) a molecule ( potassium hydroxide ,h,cl ,,ho,k ,k,cl ,,ho,h w\ld1 9 "s respects1 resemble ! ionic action ,h ,cl ,k ,,ho ,k ,cl ,,hoh4 ,! latt] w\ld probably h ! advantage ( a consid]ably small] resi/ance to ! action1 & consequ5tly ( a f> great] spe$4 ,b ! "q ( supreme importance & int]e/ to *emi/ry is ! "q z to :i* actions are f\nd exp]im5tally to be ( mom5t 9 any giv5 case4 ,n[1 a great mass ( corroborative evid5ce %[s t = ! int]actions ( ionog5s 9 aque\s solutions ! ionic actions1 probably on acc\nt ( _! enorm\s spe$s1 are ! important ones4 p#jhd ,on ! o!r h&1 !re are l>ge numb]s ( comp\nds1 especially among organic sub/ances1 :i* d n appe> to ionize to a measurable ext5t & ^: actions1 9 l>ge "p at lea/1 appe> to be ! actions ( non-ioniz$ molecules4 ,x is *>act]i/ic t mo/ ( ^! actions take place at sl[1 v frequ5tly easily measurable1 rates ( spe$4 ,critical /udy %[s t ev5 = su* actions ionization (t5 plays a v important rle1 at lea/ 9 "s ( _! /ages1 & ?r\gh\t ! field ( organic *emi/ry ! intimate relations betwe5 electrical ph5om5a & *emical activity c be readily recogniz$4#adf ,b ^! relations are n obvi\s ones & d n1 z yet1 play a dom9ant rle4 ,x is because analytical *emi/ry deals pr$om9antly ) ! reactions ( ionog5s1 t ! /udy ( ! reactions ( ions w dem& our ext5d$ att5tion4 ,reactions 9 ,non-aque\s ,solutions4--,kahl5b]g#adg has made "s int]e/+ & important1 al?\gh n conclusive1 contributions to ! problem ( *emical activity ( ionog5s 9 non-aque\s solutions4 ,he has f\nd1 = in/ance1 t z9c1 left 9 contact ) a b5z5e solution ( hydrog5 *loride c>efully fre$ f moi/ure1 displaces hydrog54#adh ,cadmium1 alum9ium & magnesium1 on ! o!r h&1 d n evolve hydrog5 9 su* a solution4#adi ,! solution %[s an enorm\s resi/ance to ! passage ( an electric curr5t1 & ! conclusion is drawn by ,kahl5b]g t ! lib]ation ( hydrog5 is due to ! action ( non-ioniz$ hydrog5 *loride on ! z9c4 ,x is evid5t1#aej f ,wald5's equation %[+ ! relation betwe5 ! ioniz+ p[] & ! dielectric con/ant ( a solv5t 7p4 #fc71 t ! presumption is t hydrog5 *loride 9 b5z5e solution is n absolutely non-ioniz$1 b r t x is ioniz$ 9 traces4#aea ,no exact measurem5ts ( ! p#jhe degrees ( ionization ( hydrog5 *loride 9 b5z5e solution h be5 made2 t ! solution %[s an enorm\s resi/ance to ! passage ( ! electric curr5t & c be1 at be/1 v little ioniz$1 is all t has be5 e/abli%$4 ,9 default ( exact data1 ! semiquantitative det]m9ation by ,kabluk(f1 %[+ t a #j4be mol> solution ( hydrog5 *loride 9 b5z5e has a resi/ance ( #abj #ajf ohms1 is ( int]e/4 ,f ! meag] data conc]n+ ! dim5sions ( ! electrodes us$1 "o may calculate 7) ! aid ( a n unreasonable assumption z to ! limit+ value ( ! conductivity1 at inf9ite solution7 t ! degree ( ionization ( ! acid 9 ! solution is p]haps ( ! ord] #e;,e#i1 & ! conc5tration ( hydrog5-ion1#aeb consequ5tly1 r\ghly #aji4 ,n[1 ! evolution ( hydrog5 by means ( z9c1 9 aque\s solutions1 takes place accord+ to ! equation ,zn 1 #b ,h ,zn#b ,h#b 1 & dep5ds on a ratio ( ! conc5trations ( z9c-ion & hydrog5-ion#aec 7,*apt]s ,,xiv & ,,xv1 q4v474 ,ev5 if ! conc5tration ( hydrog5-ion is v small1 z9c w lib]ate hydrog51 provid$ ! conditions are su* t ! conc5tration ( z9c-ion _c rea* a l>ge en\gh value to satisfy ! equilibrium ratio1 & /op ! action4 ,n[1 9 an alkal9e solution1 z9c-ion is conv]t$ into z9cate-ion 7,zn#b #d ,,ho ,zn,o#bb #b ,,hoh7 & a l>ge conc5tration ( z9c-ion _c accumulate4 ,! consequ5ce is t z9c lib]ates hydrog5 freely ev5 f alkal9e solutions1 = in/ance f mol> solutions ( potassium hydroxide1 9 :i* ! conc5tration ( hydrog5-ion1 r\ghly #ajad1 is v mu* small] ?an t calculat$ = ! b5z5e solution ( hydrog5 *loride 7namely1 #aji74 ,n[1 al?\gh ! values ( ! solution-t5sion con/ants ( elem5ts *ange mo/ decid$ly ) a *ange ( solv5t1 x seems likely#aed t _! ratios1 on :i* _! mutual displacem5t dep5ds1 w n be f\nd mat]ially alt]$4 ,z9c *loride be+ insoluble 9 b5z5e1 ! ratio = equilibrium may n be fulfill$ = z9c 9 contact ) a b5z5e solution ( hydrog5 *loride4 ,h5ce1 ) t solv5t1 ! evolution ( hydrog5 may1 s f> z x goes1 v well be due to precisely ! same ma*9]y z t op]at+ 9 aque\s solution4 ,! lib]ation goes on until ! metal is protect$ aga9/ any fur!r action by a film ( ! solid *loride4 ,x seems1 !re=e1 at lea/ possible1 t ! evolution ( hydrog5 obs]v$ by ,kahl5b]g & 8 collaborators#aee is a purely ionic action1 ! same z ! simil> p#jhf action 9 aque\s solution has be5 prov$ to be by quantitative measurem5ts4#aef ,only exact measurem5ts1 comp>able ) ^? made 9 aque\s solutions1 c settle ! "q at issue1 & until su* quantitative evid5ce is =?com+1 a def9ite conclusion t ! action ( hydrog5 *loride 9 b5z5e solution is or is n an ionic action is n w>rant$ by ! facts4 ,equally int]e/+ are ,kahl5b]g's obs]vations ( int]action betwe5 hydrog5 *loride 9 b5z5e solution & a simil> solution ( copp] oleate4 ,ea* solution %[s abs5ce ( appreciable conductivity1 yet1 :5 ! solutions are mix$1 precipitation ( copp] *loride occurs in/antly4 ,:e!r we h "h an in/antane\s action betwe5 non-ioniz$ molecules1 z claim$ by ! obs]v]1 or :e!r ! m9imal ionization#aeg ( ! hydrog5 *loride & copp] oleate1 ! exi/5ce ( :i* we h a "r to assume1 is suffici5t to acc\nt = ?is rapid action1 bo? compon5ts be+ 9 solution & intimately mix$1 is a "q ( ! greate/ int]e/4 ,b until quantitative measurem5ts ( all ! factors involv$ 9 *emical actions 9 b5z5e solution are obta9$1 a v difficult1 b necess>y task1 :i* ! discov]] ( ! action omitt$ to p]=m1 no def9ite conclusion :atev] c be bas$ on su* results1 int]e/+ z !y are4 ,wat]1 al?\gh x is only m9imally ioniz$ 7tables1 ,*apt] ,,vi71 hydrolyzes salts l potassium cyanide & alum9ium *loride almo/ in/antly1 & x has be5 rigor\sly prov$ t ! result+ condition ( equilibrium involves ! ions ( wat]#aeh 7,*apt] ,x74 ,) ! possibility t ! well-kn[n enorm\s spe$s ( action ( ions may completely (fset ! trem5d\s r$uction 9 conc5tration ( ! hydrog5-ion1 9 a b5z5e solution ( hydrog5 *loride z comp>$ ) an aque\s solution1 fur!r analysis ( ! relations is imp]ative4#aei ,until su* inve/igations h be5 c>ri$ out1 we mu/ consid] p#jhg x possible t ! reactions ( hydrog5 *loride 9 b5z5e solution may be reactions ( its non-ioniz$ molecules or reactions ( its ions4 ,9 view ( ! und\bt$ m9ute conc5trations ( ! latt]1 z comp>$ ) aque\s solutions1 & 9 view ( ! in]tness ( non-ioniz$ hydrog5 *loride 9 aque\s solutions z comp>$ ) ! activity ( its ions1 a b5z5e solution ( hydrog5 *loride %\ld %[ f> less ionic activity ?an an aque\s solution1 & t su* is ! case is br\ght out cle>ly by ,kahl5b]g's int]e/+ exp]im5ts4 ,"s ,applications ( ! ,*emical ,activity ( ,ions to ,qualitative ,analysis4--,! k t aque\s solutions ( ionog5s %[ ! reactions ( ! ions conta9$ 9 !m1 gives u a cle>1 %>ply def9$ int]pretation ( _m ( ! simpl] facts ( qualitative analysis4 ,! elem5t>y obs]vation t a l>ge numb] ( hydrog5 d]ivatives %[ acid prop]ties & a consid]able numb] ( o!rs d n 7at lea/ n to a suffici5t ext5t to be appreciable71 f9ds its simple/ explanation 9 ! fact t all solutions %[+ acid prop]ties h ^! prop]ties z ! result ( ! pres5ce ( a common compon5t1 namely ! hydrog5-ion4 ,! acid prop]ties are1 9 fact1 ! prop]ties ( ?is "o sub/ance & no o!r4 ,?us hydro*loric1 nitric1 sulphuric1 c>bonic acids are acids because !y are dissociat$ m or less1 lib]at+ hydrog5 ions2 & comp\nds l m>%-gas ,,*#d1 ammonia ,,nh#c1 b5z5e ,c#f;,h#f1 9 spite ( ! pres5ce ( a great deal ( hydrog5 9 _! molecules1 are n acids1 because !y d n1 to an appreciable ext5t1#afj ionize z d ! fir/ comp\nds m5tion$4 ,9 ! same way1 glyc]9e ,c#c;,h#e7,,oh7#c1 al?\gh x is a trihydroxide1 does n %[ ! *>act]i/ic actions ( ! hydroxides ( potassium1 b>ium1 alum9ium1 ( ! metal hydroxides 9 g5]al--! latt] are m or less ioniz$1 =m+ ! *>act]i/ic ion ( bases1 ! hydroxide-ion ,,ho2 b glyc]9e does n appe> to ionize into ,c#c;,h#ec & ,,ho4 ,! well-kn[n obs]vation ( qualitative analysis1 t potassium *lorate solutions d n precipitate silv] *loride f silv] nitrate1 :ile potassium *loride & o!r *lorides d s at once1 is n[ und]/ood z be+ ! result ( ! fact t ! *lorates produce ! *lorate-ion ,cl,o#c 7see page #gj = ! me?od ( det]m9+ its composition71 :ile ! *loride-ion p#jhh is requir$ = ! precipitation ( silv] *loride4 ,*lorplat9ic acid ,h#b,pt,cl#f1 9 spite ( ! l>ge proportion ( *lor9e 9 its composition1 does n precipitate silv] *loride1 b r silv] *lorplat9ate1#afa a yell[ salt1 insoluble 9 ammonia1 & x does s because its ions#afb are ,h & 7,pt,cl#fb74 ,p]haps ! mo/ in/ructive case ( ?is k9d1 t we c /udy1 is t ( iron 9 f]r\s & f]ric salts4 ,exce$+ly s5sitive te/s are kn[n = ! f]r\s & ! f]ric ions4 ,?iocyanates produce an int5sely r$ salt1 ,fe7,,scn7#c1 :5 add$1 = in/ance1 to f]ric *loride2 potassium f]rocyanide1 ,k#d;,fe7,,cn7#f1 precipitates f]ric f]rocyanide1 ,fe#d;,fe7,,cn7#fc1 ,prussian blue1 f f]ric *loride solutions2 ammonium hydroxide precipitates quantitatively ! insoluble r$ f]ric hydroxide 7exps474 ,) f]r\s salts1 potassium f]ricyanide ,k#c;,fe7,,cn7#f precipitates f]ro-f]ricyanide ,fe#c;,fe7,,cn7#fb1 ,turnbull's blue2 ammonium sulphide precipitates black f]r\s sulphide 7exps474 ,n[1 9 two ( ! reag5ts us$1 potassium f]ro- & f]ricyanide1 iron is pres5t accord+ to ! =mul giv54 ,if "o %\ld attempt to demon/rate its pres5ce by means ( ^! te/s--among ! mo/ s5sitive & mo/ reliable te/s kn[n 9 analysis--"o w\ld fail utt]ly4 ,?iocyanates d n produce ev5 ! fa9te/ t+e ( p9k 9 potassium f]ricyanide solution#afc2 ammonium hydroxide does n precipitate any f]ric hydroxide 7exps474 ,ammonium sulphide does n precipitate ! lea/ trace ( a black sulphide f a f]rocyanide solution1 & :5 ! latt] is mix$ ) ! f]ricyanide solution1 no trace1 ei!r ( ,prussian or ,turnbull's blue1 is %[n 7exps474 ,! contra/ betwe5 ! behavior ( ^! salts & f]r\s & f]ric salts is n[ %>ply & def9itely int]pret$1 z be+ ! result ( ! contra/ 9 _! ionization1--! color te/s we use are extremely s5sitive te/s only = ! f]ric & f]r\s ions1 ,fe#c & ,fe#b1 respectively1--b potassium f]rocyanide ionizes into potassium ions & ! negative f]rocyanide ions ,fe7,,cn7#fd1 & %[s ! actions ( f]r\s ions z little z *lorate ions ,cl,o#c exhibit ! reactions ( *loride ions ,cl4 ,potassium f]ricyanide1 9 turn1 gives rise to trival5t1 negative f]ricyanide ions ,fe7,,cn7#fc & n to f]ric p#jhi ions4#afd ,if any d\bts arise on ?is po9t1 "o c decide ! "q readily by exp]im5t4 ,:5 a conc5trat$ solution ( potassium f]ricyanide is plac$ 9 a ,u-tube "u a solution ( "s colorless electrolyte1 su* z sodium sulphate1 & plates connect$ ) a batt]y are ins]t$1 !re is no difficulty 7exp47 9 see+ t ! yell[ ion1#afe conta9+ ! iron1 moves to ! positive pole & n to ! negative4 ,! iron is1 !re=e1 z a matt] ( exp]im5t1 "p ( a negatively *>g$ sub/ance4 ,t iron is really pres5t 9 ^! comp\nds c be %[n mo/ effectively if we de/roy ! salts3 ,,exp4 ,dry1 pulv]iz$ potassium f]rocyanide is intimately mix$ ) dry potassium c>bonate & ! mixture heat$ 9 a h>d glass te/ tube4 ,:5 ! :ole mass has become r$-hot1 insur+ complete decomposition1 ! hot 7n r$-hot7 tube is plung$ into wat]2 ! salts are extract$ & p>ticles ( metallic iron are left undissolv$4 ,! action is ,k#d;,fe7,,cn7#f ,k#b;,,co#c #f ,,kcn ,fe,c,o#c ,fe,c,o#c ,fe,o ,,co#b & ,fe,o ,,kcn ,,kcno ,fe4 ,if ! iron is dissolv$ 9 a little dilute hydro*loric acid & oxidiz$ to ! f]ric condition1 by ! addition ( a few drops ( brom9e wat]1 ! int5sely r$ solution *>act]i/ic ( f]ric salts may be readily obta9$1 :5 a ?iocyanate is add$ to ! solution4 ,,footnotes3 #aad ,loomis4 7,cf4 ,:e?am1 ,!ory ( ,solution1 p4 #cbj 7#aijb747 #aae ,loomis2 & ,e4 ,h4 ,griffi?4 7,cf4 ,:e?am1 loc4 cit47 #aaf ,express$ 9 moles p] lit]4 #aag #a 3 #b444 ,c#a 3 ,c#b444 or #a _/ ,c#a #b _/ ,c#b a con/ant4 #aah ,cf4 ,:e?am1 loc4 cit41 pp4 #adg1 #aeh4 #aai ,ibid41 p4 #cbj4 #abj ,9 reg>d to ! degrees ( ionization1 z %[n by freez+-po9t depressions & conductivities ( salts1 see also ,a4 ,a4 ,noyes1 ,report ( ! ,congress ( ,arts & ,sci5ces1 ,/4 ,l\is1 #aijd1 ,vol4 ,,iv1 p4 #cac4 #aba ,see ,*apt] ,,xii1 9 reg>d to s-call$ complex ions & _! salts4 #abb ,! t]m acid ion is us$ to designate ! acid radical1 :5 x exi/s1 9 solution1 z an indep5d5t *>g$ p>ticle or ion4 ,acid ion is ?us a conv5i5t synonym = anion1 j z metal ion1 designat+ ! metal or metal-l radical ( a salt1 is us$ z a synonym = cation4 ,! t]m1 acid ion1 has be5 f\nd to convey m quickly & def9itely to ! /ud5t's m9d1 ?an does ! t]m anion1 :i* compon5t ( an acid or salt is ref]r$ to4 ,:ile x is n1 9 "s respects1 an ideal t]m1 yet its use seems ju/ifi$ by its v close relation to ! t]m acid radical & by its practical advantages4 #abc ,! pr9ciple 0 fir/ appli$ by ,hittorf4 #abd ,?is does n preclude ! possibility t ! ion is comb9$ ) m or less wat] & is ,na7,h#b,o7x2 see pp4 #db1 #fe4 #abe ,bak]1 ,j4 ,*em4 ,soc4 7,london71 #fe1 #faa 7#ahid71 #gc1 #dbb 7#ahih74 ,on page #fbc ( ! fir/ article is giv5 a li/ ( *emical actions = :i* ! effect ( ! pres5ce ( moi/ure has be5 inve/igat$ 7,/ud474 #abf ,hughes1 ,phil4 ,mag41 #cd1 #aag 7#ahib7 7,/ud474 #abg ,gore1 ,proc4 ,royal ,soc41 #ad1 #bjd 7#ahda74 ,gore f\nd t alum9ium 0 dissolv$ & t sodium & potassium 7 attack$ by ! gas1 ev5 be=e its liquefaction4 ,x is unc]ta9 :e!r ^! positive reactions are reactions ( absolutely anhydr\s hydrog5 *loride or ! result ( ! pres5ce ( moi/ure 9 ! exp]im5ts 9 "q1 s9ce ,coh5 ,*em4 ,news1 #ed1 #cje 7#ahif71 dry+ ! gas m c>efully ?an did ,gore1 f\nd1 9 contra/ to ! latt]1 t metallic sodium may be expos$ = sev]al weeks to dry hydrog5 *loride gas & reta9 its lu/re4 ,9 all exp]im5ts dem&+ ! rigor\s exclusion ( moi/ure1 m weight mu/ be atta*$ to negative results 7%[+ lack ( activity7 ?an to positive results4 ,cf4 ! controv]sy betwe5 ,bak]1 loc4 cit41 & ,gutmann1 ,liebig's ,ann41 #bii1 #c 7#ahih74 #abh ,n]n/'s ,!oretical ,*emi/ry1 p4 #cge4 ,kabluk(f1 ,z4 phys4 ,*em41 #d1 #dcj 7#ahhi74 #abi ,9 reg>d to ! behavior ( z9c1 see bel[1 p4 #hd4 7,cf4 ,kahl5b]g1 ,j4 ,phys4 ,*em41 #f1 #ac 7#aijb7 7,/ud4747 #acj ,= a full] discussion ( ! b5z5e solution see p4 #hd4 #aca ,! acid "*1 9 p>ticul>1 is due to ! hydrog5-ion1 ,h2 see bel[4 #acb ,! fusion is conv5i5tly made 9 a plat9um di%2 ! di% & a plat9um ca?ode are connect$ ) ! light+ circuit & an electric lamp4 #acc ,see ,smi?1 ,inorganic ,*emi/ry1 pp4 #eej1 #efi1 #egh1 #ehh1 #fjh1 #faj1 #fhc3 ,college ,*emi/ry1 #cfa1 #cgc1 #chj1 #chi1 #djd1 #dje1 #ddc 7,/ud474 #acd ,j4 ,*em4 ,soc4 7,ab/racts7 7,london71 #dj1 #ejd 7#ahha74 #ace ,= positive evid5ce ( ! ioniz+ p[] ( light1 see ,hab]1 ,z4 ,elektro*em41 #aa1 #hdg 7#aije74 ,= evid5ce z to ! negligible rle ( ionization 9 ! comb9ation ( *lor9e & hydrog51 see ,mellor1 ,*emical ,/atics & ,dynamics 7#aijd71 p4 #bij4 #acf ,! app>atus describ$ by ,a4 ,a4 ,noyes & ,blan*>d = comp>+ acids is us$ ,j4 ,am4 ,*em4 ,soc41 #bb1 #gcg 7#aijj74 #acg ,! conductivity dep5ds 9 ?is case *iefly on ! migration ( ! fa/ mov+ hydroxide ions 7p4 #ef71 common to ! ?ree bases4 ,!re is little diff]5ce 9 ! rates at :i* ! cations move4 #ach ,! wat] %\ld be free f c>bonic acid4 #aci ,! v>i\s indicators %[ diff]5t1 specific degrees ( s5sitiv5ess to acids 7to hydrog5 ions7 & to bases 7to hydroxide ions74 ,t is1 diff]5t conc5trations ( hydrog5-ion or ( hydroxide-ion are requir$ to *ange _! colors4 ,z !y are p>ticul>ly useful 9 demon/rat+ v>y+ conc5trations ( ^! ions1 !y w frequ5tly be us$ 9 illu/rat+ conclusions rea*$ 9 ! c\rse ( our "w1 j z !y are us$ ext5sively 9 practical analysis4 ,! foll[+ tables are int5d$ to give "s def9ite in=mation on ?is valuable quality4 ,! f\r? column ( ! fir/ table %[s ! conc5tration ( hydrog5-ion1 requir$ to *ange ! color ( ! indicator f ! t9t giv5 9 ! second column to ! t9t giv5 9 ! ?ird column4 ,! second table gives1 simil>ly1 ! conc5trations ( hydroxide-ion requir$ to produce ! *anges ( t9t indicat$4 ,! tables ref] to results obta9$ :5 #j4a c4c4 7ab\t two drops7 ( a #j4a to #j4ae solution ( ! indicator is add$ to #aj c4c4 ( ! solution exam9$4 ,,table ,,( ,,s5sitiv5ess ,,to ,,acids 7,,to ,,hydrog5-,,ion7 ,indicator4 ,f to ,conc5tration ,h4 ,ph5olph?alen ,p9k ,colorless #aj;,e#i ,azolitm9,a 7litmus7 ,violet ,violet p9k #a;,e#f ,me?yl orange ,yell[ ,r$di% orange #a;,e#c - #j4a;,e#c ,,table ,,note3 ,a4 ,azolitm9 is an important compon5t ( litmus4 ,,table ,,( ,,s5sitiv5ess ,,to ,,bases 7,,to ,,hydroxide-,,ion7 ,indicator4 ,f to ,conc5tration ,,ho4 ,ph5olph?alen ,colorless ,p9k #aj;,e#f ,azolitm9 ,violet ,violet blue #a;,e#f - #j4a;,e#f ,me?yl orange ,orange ,yell[ #a;,e#i ,x is cle> t ( ! ?ree indicators giv5 9 ! table1 ph5olph?alen is ! mo/ s5sitive to acids1 me?yl orange ! mo/ s5sitive to bases4 ,an ext5d$ table ( ! s5sitiv5ess ( _m indicators1 on :i* ! above tables are bas$1 is giv5 by ,salm1 ,z4 phys4 ,*em41 #eg1 #dga 7#aijg74 ,! !ories 7( ,o/wald1 ,b]n?s51 & o!rs7 reg>d+ ! color *anges1 & ! !ory 7( ,o/wald7 conc]n+ ! s5sitiv5ess ( indicators1 are discuss$ 7) ref]5ces to ! lit]ature7 by ,/ieglitz1 ,j4 ,am4 ,*em4 ,soc41 #be1 #aaag 7#aijc74 ,lat] modifications ( ! views on color *anges are discuss$ 9 pap]s by ,/ieglitz1 ,am4 ,*em4 ,j4 #ci1 7#aijh71 & by ,acree1 ibid41 #cg1 #ci1 #db1 & 9 ^! pap]s ref]5ces to ! lit]ature w be f\nd4 ,= inve/igations on ! s5sitiv5ess ( indicators1 see ,mc,coy1 ibid41 #ca1 #ejh 7#aijd71 ,salm1 loc4 cit41 & ,a4 ,a4 ,noyes1 ,j4 ,am4 ,*em4 ,soc41 #cb1 #hae 7#aiaj74 #adj ,z4 phys4 ,*em41 #b1 #bhi 7#ahhh74 ,note ! rem>ks 9 ! footnote foll[+4 #ada ,! =mation ( an ammonium salt 9 ! latt] action /ill fur!r r$uces ! conc5tration ( ! hydroxide-ion 7,*apt] ,,vi7 & ret>ds ! action2 b ! solution1 9 equal measure1 becomes less active t[>d ! indicator1 ph5olph?alen 7p4 #aad74 ,! exp]im5t %[s1 !re=e1 r fairly1 ! relative activities ( ! bases4 ,! exact "w ( ,arrh5ius includ$ consid]ation ( ! effect ( ! ammonium salt1 & ! cle>+ up ( ! my/]y ( ?is effect 7p4 #aad7 =m$ "o ( ! greate/ triumphs ( 8 !ory4 #adb ,arrh5ius1 ,electro-*emi/ry1 p4 #ahd 7#aijb74 ,a second accel]ative factor1 ! s-call$ salt effect 7,*ap4 ,,vi1 q4 v471 is m pron\nc$ 9 ! case ( #j4a mol> hydro*loric acid ?an 9 t ( #j4a mol> acetic acid1 z ! result ( :i* ! activity ( ! hydro*loric acid %\ld be increas$ ab\t t5 p] c5t2 ! ratio1 !re=e1 ( ! spe$s ( reaction1 bo? ! degrees ( ionization ( ! acids & ! salt effect be+ consid]$1 %\ld be approximately #hc 3 #a1 :]eas ! ratio f\nd by exp]im5t is #gi 3 #a4 #adc ,vide also ,a4 ,a4 ,noyes1 ,report ( ! ,congress ( ,arts & ,sci5ce1 ,vol4 ,,iv1 p4 #caa 7#aijd74 #add ,hab]1 ,z4 fr ,elektro*em41 #aj1 #gge 7#aijd72 see ,*apt] ,,xii4 #ade ,?is is1 ess5tially1 ! old ,b]zelius view ( *emical action4 #adf ,vide1 = in/ance1 ,/ieglitz1 ,report ( ! ,congress ( ,arts & ,sci5ces1 ,/4 ,l\is1 ,,iv1 #bgf 7#aijd72 ,w4 ,a4 ,noyes1 ,ibid41 #bhe2 ,nef1 ,j4 ,am4 ,*em4 ,soc41 #cj1 #fde 7#aijh74 ,= ! application ( ! electron !ory to organic comp\nds1 see ,falk & ,nelson1 ,s*ool ( ,m9es ,qu>t]ly1 #cj1 #agi1 & ,j4 ,am4 ,*em4 ,soc41 #cb1 #afcg 7#aiaj74 7,cf4 also ,*apt] ,,xv47 #adg ,j4 ,phys4 ,*em41 #f1 #a 7#aijb71 & o!r pap]s 9 ! same ,j\rnal4 #adh ,cf4 ,patt51 ibid41 #g1 #afh 7#aijc71 & ,falk & ,wat]s1 ,am4 ,*em4 ,j41 #ca1 #cih 7#aijc74 ,accord+ to ! latt] inve/igators1 ! evolution ( hydrog5 is sl[ & weak4 #adi ,patt51 loc4 cit4 #aej ,/ud5ts w n be capable ( foll[+ ! argum5t giv5 9 ! succe$+ passages & w\ld bett] omit ?is "p until ,*apt] ,,xv has be5 /udi$4 #aea ,kabluk(f1 ,z4 phys4 ,*em41 #d1 #dcj 7#ahhi74 ,see also ,n]n/1 ,!oretical ,*emi/ry1 p4 #cgc4 #aeb ,9 view ( ! l[ ord] ( accuracy ( ! data1 & ( ! approximate me?od ( calculation1 ?is result is only qualitative1 b ev5 ) an error ( #ajb to #ajd ! argum5t 9 ! text w\ld hold4 #aec ,= hydrog5 "u atmosph]ic pressure1 ! equilibrium ratio1 ,zn#b _/ ,h#b1 is1 approximately1 #ajbg4 #aed ,vide ,sackur1 ,z4 ,elektro*em41 #aa1 #chg 7#aije74 ,kahl5b]g holds a diff]5t view2 ibid4 #aee ,! negative results obta9$ ) alum9ium & magnesium are possibly m int]e/+ ?an ! positive action obs]v$ ) z9c1 b _! inactivity may be due to ?9 films ( protective *loride or oxide or to a passive condition 7vide ,smi?'s ,inorganic ,*emi/ry1 pp4 #gbc1 #gec2 ,college ,*emi/ry1 p4 #dge74 #aef ,! "w ( ,o/wald1 ,arrh5ius1 ,n]n/ & _m o!rs %[s conclusively t ! lib]ation ( hydrog5 by metals & ! precipitation ( metals by "o ano!r is a function ( ion conc5trations 7,*apt] ,,xiv74 ,vide ,n]n/1 ,!oretis*e ,*emie 7#aije71 p4 #bde4 #aeg ,see above4 #aeh ,9 a #j4a mol> solution ( potassium cyanide1 ! potassium hydroxide =m$ by ! decomposition ( ! cyanide by wat] is approximately #j4jjac mol> & ! conc5tration ( hydrog5-ion is r$uc$ to #ajaa 7,*apt] ,x71 a value r\ghly ( ! same ord] z t calculat$ above z a possible conc5tration ( hydrog5-ion 9 a b5z5e solution ( hydrog5 *loride4 ,9 spite ( ?is small conc5tration ( hydrog5-ion 9 ! cyanide solution1 ! reactions 9 :i* x is involv$ are1 z f> z kn[n1 complet$ 9 a few mom5ts4 ,only = mu* small] conc5trations ( ions h any d\bts z to _! direct action be5 ar\s$2 9 ,*apt] ,,xii ?is "q1 z rais$ by ,hab]1 is discuss$ = conc5trations ( ions ( ! ord] ( #ajbc4 ,hab] consid]s t ionic conc5trations ( #ajad c /ill acc\nt = v fa/ actions4 #aei ,cf4 ,abegg41 ,!orie d] ,elektrolytis*5 ,dissociation 7#aijc71 #bee2 ,lehfeldt1 ,electro-*emi/ry 7#aijd71 #hg4 #afj ,!re is probably m9imal ionization 9 all ^! cases1 especially 9 ! case ( ammonia 7,,nh#c ,,nh#b ,h71 b n en\gh to yield a suffici5t supply ( hydrog5-ion to %[ its common prop]ties4 #afa ,vide ,jorg5s51 ,j4 prakt4 ,*em41 #af1 #cdi 7#ahgg74 #afb ,see ,*apt] ,,xii 9 reg>d to ! /ability ( 7,pt,cl#fb7 z a complex ion4 #afc ,fre%ly prep>$ solutions mu/ be us$4 #afd ,see ,*apt] ,,xii z to ! decomposition ( ! complex ions4 #afe ,k & ,,cn are colorless ions4 ,! yell[ color ( ! ion mov+ to ! positive electrode %[s ! pres5ce ( ! iron 9 x--a fact t c be confirm$ by te/+ ! solution r\nd ! anode = f]ricyanide by ! me?od discuss$ fur!r on 9 ! text4 p#jij ,,*apt] ,,vi ,,*emical ,,equilibrium4 ,,! ,,law ,,( ,,mass ,,action ,! !ory ( ionization1 z /udi$ s f>1 gives u simple1 rational explanations ( _m ( our qualitative reactions--explanations :i* agree ) ph5om5a tak5 f sep>ate fields ( inve/igation4 ,b1 if our /udy ( ! !ory ceas$ at ! pres5t /age )\t fur!r elaboration1 we %\ld fail to f9d 9 x a satisfactory explanation ( a numb] ( o!r important facts ( analysis--notably1 :y c]ta9 reactions1 ! occurr5ce ( :i* we might anticipate1 d n take place4 ,= in/ance1 ! addition ( a soluble c>bonate to a b>ium *loride solution precipitates almo/ all ! b>ium z b>ium c>bonate 7exp472 we h #b ,na ,,co#cb ,ba#b #b ,cl ,ba,c,o#c #b ,na #b ,cl4 ,b ! addition ( c>bonic acid to b>ium *loride solutions fails to produce ! slighte/ precipitate 7exp471 al?\gh c>bonic acid also gives rise to ! c>bonate-ion1 ,,co#cb4 ,9 ! same way silv] nitrate readily precipitates silv] phosphate f sodium phosphate solutions 7exp471 b n f a solution ( phosphoric acid 7exp474 ,hydrog5 sulphide precipitates z9c sulphide f a z9c sulphate solution 7exp471 ,zn#b ,,s#db #b ,h ,s#b ,zn,s #b ,h ,,s#db2 b ! addition ( hydro*loric acid effectually prev5ts ! precipitation 7exp471 al?\gh ! hydrog5 sulphide is /ill ioniz$1 z is app>5t f ! precipitation ( copp] sulphide :5 copp] sulphate is add$ to ! mixture 7exp474 ,9 ! negative results1 we h in/ances ( a v l>ge numb] ( cases :i* require clos] /udy1 & a fur!r developm5t ( ! !ory1 if we wi% to int]pret !m satisfactorily4 ,! l9e ( developm5t to be foll[$ is indicat$ p]haps mo/ %>ply by ! foll[+ exp]im5t4 ,,exp4 ,"s sodium tetraborate 7borax7 is dissolv$ 9 a little wat] & silv] nitrate is add$ to a small "p ( ! solution4 ,a pure :ite precipitate 7silv] borate7 results4 ,ano!r portion ( ! borate solution is dilut$ ) a l>ge quantity ( wat]1 & !n silv] nitrate is add$2 q a diff]5t result is obta9$--a br[n precipitate 7silv] oxide7 is =m$4 p#jia ,! *ange 9 ! quantity ( wat] br\ght ab\t ! diff]5ce 9 result--! quantitative relations 7 alt]$ !reby4 ,9 ord] to foll[ intellig5tly ?is & ! o!r actions ref]r$ to1 ! /udy ( reactions 9 solutions mu/ be tak5 up f ! quantitative side--! developm5t h]et(ore has be5 ess5tially qualitative 9 "*4 ,on sev]al occasions we h f\nd t all electrolytes d n ionize equally well1 & t ! int5sity ( _! action1 demon/rat$1 = in/ance1 = potassium & ammonium hydroxides1 v>ies accord+ly4 ,we %all n[ h to /udy ^! relations 9 great] detail4 ,= our purpose1 ! /udy ( two ( ! fundam5tal quantitative laws gov]n+ action 9 solution & ( _! application to analytical ph5om5a1 w be suffici5t3 ^! are1 ! law ( *emical or homog5e\s equilibrium1 9 :i* ! law ( mass action is includ$1 & ! law ( physical or het]og5e\s equilibrium4 ,! ,law ( ,*emical ,equilibrium4--,! law ( *emical equilibrium may be express$1 = a simple case1 by say+ t if two sub/ances ,a & ,b int]act at a con/ant temp]ature to give two comp\nds ,c & ,d &1 vice v]sa1 ,c & ,d int]act ) ea* o!r to produce ,a & ,b1 !n equilibrium w be rea*$ :5 ! ratio ( ! product ( ! conc5trations ( ,a & ( ,b to ! product ( ! conc5trations ( ,c & ( ,d has a def9ite1 con/ant value1 :i* is a value *>act]i/ic ( ! equilibrium betwe5 ! comp\nds involv$1 at ! giv5 temp]ature4 ,! action may be express$ 9 ! *emical equation ,a ,b ,c ,d1 9 :i* ,a1 ,b1 ,c & ,d repres5t f\r diff]5t sub/ances react+ 9 ! molecul> proportions indicat$ by _! symbols1 :i* z usual repres5t molecul> weights4 ,& ! condition = equilibrium may be express$ 9 ! ma!matical equation ,a ,b _/ 7,c ,d7 k4 ,a1 ,b1 ,c & ,d are us$ to repres5t ! conc5trations#aff ( p#jib ! f\r react+ sub/ances & k is "s def9ite numb]1 call$ ! equilibrium con/ant4 ,! law 0 discov]$ by ,guldb]g & ,waage 9 #ahfg1 &1 ) c]ta9 limit+ conditions 7see bel[7 x has be5 fully e/abli%$ by ext5sive exp]im5tal "w4#afg ,! significance ( ! law may be int]pret$ on ! basis ( ! foll[+ consid]ations4 ,if we />t ) ! two sub/ances ,a & ,b alone & h "o mole ( ea* 9 "o lit] 7z gas or 9 solution7 at a giv5 temp]ature1 !n1 all ! conditions be+ giv51--! temp]ature1 ! conc5trations1 & ! nature ( ! sub/ances1--! reaction ,a ,b ,c ,d1 lead+ to ! =mation ( ,c & ,d1 w proce$ ) a p]fectly def9ite velocity4 ,! molecules ( ,a & ( ,b move 9 all directions 7k9etic !ory ( gases & solutions71 & molecules ( ,a w collide ) molecules ( ,b a def9ite numb] ( times 9 unit "t & w =m a def9ite numb]#afh ( molecules ( ,c & ,d p] m9ute4 ,! velocity ( *emical *ange ( a giv5 sub/ance 7*emical velocity7 is also measur$ 9 t]ms ( moles1 & is repres5t$ by ! numb] ( moles or ! fraction ( a mole *ang$ p] m9ute4 ,if v#a /&s = ! velocity ( ! action betwe5 ,a & ,b1 "u ! giv5 conditions1 !n v#a k#a1 :]e k#a is "s numb]4 ,n[1 if ! conc5tration ( "o ( ! compon5ts1 e4g4 ,a1 %\ld be d\bl$1 !n ! *ances = collision & = action betwe5 molecules ( ,a & ,b w be twice z great z be=e & ! velocity ( ! action w be d\bl$4 ,if only "o-t5? ( ! conc5tration ( ,a 7"o-t5? mole7 is us$1 ! velocity w only be "o-t5? z great z orig9ally1 &1 9 g5]al t]ms1 if ,a moles ( ,a are us$ p] lit]1 ! velocity ( ! *ange w be proportional to ,a1 & equal to k#a ,a4 ,if ! conc5tration ( ! o!r react+ compon5t1 ,b1 is n[ d\bl$1 ! *ances = action are aga9 d\bl$1 &1 9 g5]al1 ! velocity ( ! action w be proportional also to ! conc5tration p#jic ,b ( ! second react+ sub/ance4 ,= ! velocity1 v#a ( ! action = any conc5trations1 ,a & ,b1 ( ,a & ,b at any mom5t at a giv5 temp]ature1 we h v#a k#a ,a ,b4 ,h5ce1 if by ! symbols ,a & ,b ! conc5trations at any giv5 mom5t are repres5t$1 we may say t ! velocity ( ! =mation ( ,c & ,d at t mom5t#afi is proportional to ! product ( ! conc5trations ( ,a & ,b1 & to "s con/ant1 :i* is *>act]i/ic ( ! int]action ( ,a & ,b4 ,! validity ( ?is conclusion has be5 fully v]ifi$ by exp]im5t4#agj ,! case is an in/ance ( ! law ( mass action1 :i* /ates t 9 *emical *anges ! velocity ( ! action is proportional at any mom5t to ! molecul> conc5trations#aga ( ! react+ compon5ts1 & to a con/ant1 :i* is *>act]i/ic ( ! *emical nature ( ! react+ compon5ts 7& ( ! temp]ature74 ,if we />t ) ! rev]s$ action ,a ,b ,c ,d1 ! relation may be develop$ 9 ! same way4 ,?us ! two sub/ances ,c & ,d w react ^u ea* o!r1 at ! giv5 temp]ature1 ) a velocity proportional to a con/ant1 k#b1 &1 at any giv5 mom5t1 proportional also to _! respective conc5trations at t mom5t3 v#b k#b ,c ,d4 ,equilibrium w be rea*$ :5 ! sub/ances ,a & ,b are =m$ at any mom5t f ,c & ,d j z rapidly z !y are us$ up to produce ,c & ,d1 & vice v]sa4 ,su* is ! case1 p#jid :5 ! velocities ( ! two opposite reactions are equal to ea* o!r4 ,= ! condition ( equilibrium1 !n1 v#a mu/ be equal to v#b & !re=e k#a ,a ,b k#b ,c ,d or ,a ,b _/ 7,c ,d7 k#b _/ k#a kequilibrium4 ,9 ?is way ! mean+ ( ! fundam5tal law ( *emical equilibrium may be develop$ f ! consid]ation ( ! velocities ( ! rev]sible actions1 su* z are involv$ 9 all conditions ( equilibrium1 & ! equilibrium con/ant repres5ts ! ratio ( ! velocity con/ants ( ! two opposite reactions4 ,?is conclusion has be5 fully v]ifi$ by exp]im5t1 ! equilibrium con/ant be+1 z a matt] ( fact1 f\nd equal to ! ratio ( ! velocity con/ants4#agb ,! relations1 s f> consid]$1 h be5 ^? ( ! simple/ type ( rev]sible reaction4 ,we may n[ discuss ! modifications requir$ = o!r types ( reaction by ! law ( equilibrium4 ,:5 two molecules ( any react+ compon5t take "p 9 a reaction--= in/ance1 9 ,a #b ,b ,c ,d--! conc5tration ( ?is compon5t is rais$ to ! second p[] 9 ! ma!matical expression ( ! law ( equilibrium2 :5 ?ree molecules ( a compon5t take "p1 its conc5tration is rais$ to ! ?ird p[]1 etc4 ,= in/ance1 hydrog5 iodide is decompos$1 rev]sibly1 into hydrog5 & iod9e1 accord+ to #b ,,hi ,h#b ,i#b4 ,a condition ( equilibrium is rea*$1 at a giv5 temp]ature :5 ,h#b ,i#b _/ ,,hi#b ,k4 ,at #ddj1 ! results giv5 9 ! foll[+ table 7 obta9$ by ,bod5/e94 ,! conc5trations are express$ 9 moles p] lit]4#agc ,! con/ant is calcuat$ accord+ to ! equation j giv54 ,analytical errors affect ! value ( ! con/ant mo/ 9 ! fir/ & la/ exp]im5ts1 z a result ( ! v small conc5trations ( "o compon5t1 ,i#b or ,h#b4 p#jie ,h#b ,i#b ,,hi ,k #j4jbfh #j4jjjaij #j4jagg 7#j4jaf7 #j4jjihf #j4jjbjc #j4jcbh #j4jai #j4jjcjh #j4jjghc #j4jccg #j4jba #j4jjage #j4jaad #j4jcae #j4jbj #j4jjjfec #j4jbjd #j4jbcf #j4jbd #j4jjjbfe #j4jbdb #j4jbjb 7#j4jaf7 ,! me*anical significance ( ! rais$ p[]s ( ! conc5trations ( compon5ts1 two or m molecules ( :i* take "p 9 a reaction z indicat$1 w be discuss$ fur!r on1 9 connection ) a case ( equilibrium betwe5 an electrolyte & its ions 7,*apt] ,,vi1 p4 #ajb74 ,limitations to ! ,law ( ,*emical ,equilibrium4--,q 9 agreem5t ) ! int]pretation ( ! law ( *emical equilibrium f ! view-po9t ( ! k9etic !ory1 x is f\nd t1 9 its applications1 "o mu/ take into consid]ation ! possibility1 t molecul> attractions 7p4 #bg7 or o!r important =ces ( attraction or repulsion 7e4g4 electrical7 ( a m ?an negligible magnitude exi/ betwe5 ! molecules ( ! compon5ts 9 a rev]sible reaction4 ,if su* =ces are involv$1 suitable all[ance mu/ be made = !m1 s t ! ma!matical =mulation ( ! law may express ! facts ( obs]vation4#agd ,= ^! reasons1 ! law1 9 its simple/ t]ms1 :i*1 alone1 c be consid]$ "h1 holds = ! relations obta9+ 9 dilute sy/ems#age 7dilute solutions or gases t are n too /rongly compress$71 & 9 sy/ems involv+ only nonelectrolytes or only weak ionog5s1 m g5]ally ?an = ! relations 9 conc5trat$ solutions 7or /rongly compress$ gases7 or 9 sy/ems1 9 :i* electrically *>g$ p>ticles 7ions7 are pres5t 9 l>ge proportions 7see bel[1 p4 #ajh74 ,! ,factors ( ! ,law ( ,*emical ,equilibrium4--,inspection ( ! ma!matical expression ( ! law ( *emical equilibrium 7p4 #ia7 %[s t !re are two significant k9ds ( factors 9 x3 fir/1 ! equilibrium con/ant1 ^: value dep5ds only on ! nature ( ! sub/ances involv$ & on ! temp]ature4#agf ,9 p#jif ! second place1 we h conc5tration factors1 :i*1 to a l>ge ext5t1#agg may be v>i$ at w4 ,! foll[+ exp]im5ts may be us$ to illu/rate ! significance ( ! two classes ( factors3 ,phosphorus p5tabromide is p>tially decompos$ by heat into ! tribromide & brom9e 7a case ( gase\s dissociation73 ,p,br#e ,p,br#c ,br#b4 ,phosphorus tri*lordibromide is decompos$ m or less1 9 a simil> fa%ion1 into ! compon5ts phosphorus tri*loride & brom9e1 accord+ to ! equation ,p,cl#c;,br#b ,p,cl#c ,br#b4 ,= ! condition ( equilibrium 9 ! two cases we h ,p,br#c ,br#b _/ ,p,br#e k#a & ,p,cl#c ,br#b _/ ,p,cl#c;,br#b k#b4 ,,exp4 ,two tubes conta9+ equival5t quantities ( ! two bromides are plac$ side by side 9 w>m wat]4#agh ,! tube conta9+ ! tri*lordibromide is f\nd to be mu* m int5sely color$ by free brom9e ?an t conta9+ ! p5tabromide4 ,! int5sity ( ! color ( ! brom9e vapor %[s t ! conc5tration ( brom9e1 ,br#b1 9 ! ,p,cl#c;,br#b tube1 is great] ?an ! correspond+ conc5tration1 ,br#b1 9 ! ,p,br#e tube4 ,z a molecule ( p5tahalide ,,px#e dissociates into "o molecule ( ,,px#c & "o molecule ( ,x#b1 ,p,cl#c equals ,br#b & is great] ?an ,p,br#c1 :i* is equal to ,br#b4 ,fur!r1 m ( ! p5tabromide ?an ( ! tri*lordibromide mu/ be left undecompos$1 i4e4 ,p,cl#c;,br#b is small] ?an ,p,br#e4 ,s9ce ! factors 9 ! num]ator ( ! second equation are bo? l>g]1 & ! factor 9 ! d5om9ator small]1 ?an ! correspond+ factors 9 ! fir/ equation1 k#b mu/ be great] ?an k#a4 ,^! con/ants are ?us se5 to be a measure ( ! *emical /ability ( ^! p5tahalides4 ,x is evid5t1 too1 t 9 reactions :i* dep5d on ! pres5ce ( free brom9e1 su* z ! brom9ation ( _m organic comp\nds1 ! tri*lordibromide %\ld be m effective ?an ! equival5t quantity ( ! p5tabromide4 p#jig ,9 ! second place1 if we 7 to introduce into ei!r tube1 = in/ance into ! tube conta9+ ! phosphorus tri*lordibromide1 an excess ( "o ( ! dissociation products1 say an excess ( phosphorus tri*loride1 !n ! condition ( equilibrium w\ld necess>ily be di/urb$3 y ,p,cl#c ,br#b _/ ,p,cl#c;,br#b k#b1 9 :i* ! bracket$ symbols repres5t ! conc5trations ( ! fir/ exp]im5t4 ,! velocities ( ! two opposite reactions w\ld be no long] equal1 ! comb9ation ( tri*loride ) brom9e w\ld be accel]at$ by ! increas$ conc5tration ( ! =m]4 ,"h1 equilibrium w\ld only be re/abli%$ :5 ! tri*loride & brom9e _h comb9$ to a suffici5t ext5t to make 7y ,p,cl#c x7 7,br#b x7 _/ 7,p,cl#c;,br#b x7 k#b1 9 :i* x repres5ts ! numb] ( moles ( additional phosphorus tri*lordibromide =m$ 9 unit volume by ! comb9ation ( brom9e ) phosphorus tri*loride4 ,! net result is se5 to be t an increase 9 ! conc5tration ( ! "o dissociation product eo ipso r$uces ! conc5tration ( ! o!r dissociation product4 ,,exp4 ,a ?ird tube *>g$ ) ! same quantity ( phosphorus tri*lordibromide z ! tube m5tion$ above1 & ) an add$ excess ( phosphorus tri*loride1 is plac$ 9 ! w>m wat] next to ! tube conta9+ ! tri*lordibromide4 ,its color is mu* pal] ?an t ( ! latt]1 ow+ to ! suppression ( free brom9e4#agi ,! conc5tration ( ! free brom9e1 7,br#b x71 "u ! new conditions ( equilibrium1 is small] ?an ! orig9al conc5tration ,br#b--;a result confirm$ by exp]i5ce4 ,x is 9 our p[]1 !re=e1 arbitr>ily to *ange ! conc5tration ( a react+ compon5t1 9 a case ( equilibrium1 & ?us to affect ! reactivity ( ! sy/em2 = in/ance1 = brom9at+ purposes1 ! new sy/em w\ld be less effective ?an ! orig9al "o1 & x might be ( especial s]vice :]e brom9ation is to be avoid$4 ,9 ! cases /udi$1 are f\nd ! two fundam5tally important relations express$ by ! law ( equilibrium3 ! equilibrium con/ant is a measure ( ! /ability ( a c]ta9 sy/em &1 9 a way1 ( its reactivity at a giv5 temp]ature2 & ! p#jih conc5tration factors are v>iables1 :i* we may *ange to a v consid]able ext5t1 s z1 to a c]ta9 degree1 to subject ! sy/em to our own purposes4 ,we %all repeat$ly h occasion to ref] to ^! two fundam5tal relations & we %all use !m aga9 & aga9 9 our analytical "w4 ,*emical ,equilibrium ( ,electrolytes4--,ionization ( an electrolyte is a rev]sible *emical action & its relation to ! law ( *emical equilibrium w n[ be discuss$4 ,= acetic acid1 ionization into hydrog5 & acetate ions occurs ?us3 ,,*#c;,,co#b;,h ,,*#c;,,co#b ,h1 &1 9 accordance ) ! law ( equilibrium1 at a giv5 temp]ature1 ! foll[+ relation w\ld hold3 ,h ,,*#c;,,co#b _/ ,,*#c;,,co#b;,h ,kionization4 ,if ! total conc5tration ( ! acid is kn[n1 ! conc5trations ( ! ions & ( ! non-ioniz$ acid may be calculat$ f ! conductivity ( ! solution4 ,= in/ance1 if #fj grams ( acetic acid 7#a mole7 is dissolv$ 9 suffici5t wat] to make #aj lit]s1 ! equival5t conductivity ( ! solution 7p4 #ej7 is f\nd to be #d4fg reciprocal ohms at #ah4 ,! maximum conductivity ( "o mole ( acetic acid1 at inf9ite dilution1 :5 all ! acid w\ld be ioniz$1 w\ld be #cdg4 ,!re=e1 9 ! acid "u exam9ation1 #d4fg _/ #cdg1 or #a4cd p] c5t1 is ioniz$ 7p4 #ej74 ,s9ce ! total conc5tration ( ! acid is #j4a mole p] lit] & #a4cd p] c5t is ioniz$1 ! conc5tration ( ! hydrog5-ion1 ,h1 is #j4a #j4jacd1 & t ( ! acetate-ion1 ,,*#c;,,co#b1 is ! same4 ,! conc5tration ( ! non-ioniz$ acetic acid1 ,,*#c;,,co#b;,h1 is #j4a #j4ihff4 ,if ^! values are ins]t$ 9 ! equation = ! condition ( equilibrium1 we h 7#j4a #j4jacd7b _/ 7#j4a #j4ihff7 ,kionization #ah4b;,e#f4 ,f ?is exp]im5tal result1 ! equilibrium con/ant1 :i* is call$ ! ionization con/ant ( ! acid1 is f\nd to h ! value #ah4b;,e#f4 ,if ! ratio ,h ,,*#c;,,co#b _/ ,,*#c;,,co#b;,h really is a con/ant1 ! same value1 )9 ! limits ( exp]im5tal errors1 %\ld be obta9$ f acetic acid 9 o!r conc5trations4 ,n[1 if ! above solution is dilut$ to t5 times its volume1 ! conc5tration ( ! acid is made #j4ja mole p] lit]1 ! conductivity p#jii is f\nd to h increas$ to #ad4e reciprocal ohms1 & ! p]c5tage ( ioniz$ acid is !n #ad4e _/ #cdg1 or #d4ag4 ,"h1 ,h & ,,*#c;,,co#b #j4ja #j4jdag & ,,*#c;,,co#b;,h #j4ja #j4iehc4 ,ins]t+ ^! values 9 our g5]al equation & calculat+ ! result1 we obta9 #ah4a;,e#f z ! value ( ! con/ant4 ,9 ! foll[+ table#ahj are giv5 ! mol> conductivities1 7column #b71 ( acetic acid ( v>y+ conc5trations1 m 7column #a74 ,! degrees ( ionization1 1 & ! ionization con/ant1 calculat$ accord+ to ! equilibrium equation1 are giv5 9 columns #c & #d4 ,,ionization ,,( ,,acetic ,,acid4 #cdg4 m4 4 #ajj 4 ,k4 #j4a #d4fg #a4cd #ah4b;,e#f #j4jh #e4bb #a4ej #ah4c;,e#f #j4jc #h4ej #b4de #ah4e;,e#f #j4ja #ad4ej #d4ag #ah4a;,e#f ,x is evid5t1 t a con/ant value is f\nd = ! ratio ,h ,,*#c;,,co#b _/ ,,*#c;,,co#b;,h & t ! ionization ( acetic acid1 9 ^! dilute solutions1 obeys ! law ( *emical equilibrium4#aha ,! equilibrium con/ant expresses 9 def9ite1 quantitative t]ms ! t5d5cy ( acetic acid to ionize 9 dilute solution4 ,exam9ation ( o!r acids %[s t !re is an enorm\s range 9 ! values f\nd = _! respective ionization con/ants4 ,! con/ants are ! be/ measure ( ! /r5g? ( ! acids z acids4 ,obvi\sly1 ! m readily acids 9 equival5t solutions ionize1 ! great] w be ! conc5tration ( ! hydrog5-ion to :i* ! *>act]i/ic acid prop]ties are due1 & ! m pron\nc$ 7/rong]7 w be ! exhibition ( ^! prop]ties4 ,f ! ionization con/ants "o may calculate1 = in/ance1 ! proportion 9 :i* two compet+ acids w neutralize a base1 :5 ! latt] is us$ 9 quantity insuffici5t to neutralize bo? acids4 p#ajj ,inspection ( ! equation = acetic acid1 :i* is ! typical equilibrium equation = all monobasic acids1 %[s t ! great] ! degrees ( ionization ( acids are 9 equival5t solutions1 i4e4 ! great] ! conc5trations ( ! hydrog5-ion :i* _! ionization produces 9 equival5t solutions1 ! l>g] w be ! values ( _! ionization con/ants4 ,! acids ) ! l>g] con/ants are1 !n1 ! /rong] acids4 ,! ,ionization ( ,v>i\s ,acids4--,! table giv5 on page #ajd %[s ! ionization con/ants = a numb] ( acids ( int]e/ 9 analysis4 ,be=e proce$+ to give ! table1 we mu/ consid] fur!r two important po9ts4 ,9 ! fir/ place1 = ! /ronge/ acids1 su* z hydro*loric1 nitric1 hydrobromic & simil> acids1 *emi/s h be5 unable to det]m9e ionization con/ants on ! basis ( ! law ( *emical equilibrium4 ,/rong acids1 /rong bases & mo/ salts 7see pp4 #ajf-h1 bel[71 ! ?ree classes compris+ all ! v readily ionizable electrolytes1 d n give con/ants :5 ! values ( ! equilibrium ratio1#ahb ,cation ,anion _/ ,molecules1 are calculat$ = diff]5t conc5trations1 & !y !re=e d n ionize simply 9 accordance ) ! law ( *emical equilibrium4 ,! reasons = ?is abnormal behavior w be discuss$ pres5tly 7p4 #ajh71 :5 o!r necess>y facts are be=e u4 ,9 ord] to h1 at lea/1 a r\gh basis = comp>ison ( ^! /rong acids ) ! weak ones1 :i* d obey ! law ( *emical equilibrium1 ! table w give = ! /rong acids ! value ( ! above ratio z calculat$ f _! ionization 9 #j4a mol> solutions4 ,! ,ionization ( ,polybasic ,acids4--,9 ! second place1 ! mean+ ( ! con/ants = polybasic acids1 su* z sulphuric1 phosphoric1 c>bonic & simil> acids1 requires explanation4 ,! relations = c>bonic acid w be fir/ develop$1 z repres5t+ a typical case4 ,c>bonic acid1 9 ioniz+1 =ms ! c>bonate-ion ,,co#cb1 & ! hydrog5-ion1 z express$ 9 ! p#aja equation#ahc ,h#b;,,co#c #b ,h ,,co#cb4 ,accord+ to ! law ( *emical equilibrium = ! case :]e a product 7"h ! hydrog5-ion7 appe>s twice on "o side ( ! reaction equation1 we h1 = ! condition ( equilibrium 7p4 #id7 ,h#b ,,co#cb _/ ,h#b;,,co#c ,k4 7#a7 ,we may ask1 h[ev]1 :e!r bo? ! hydrog5 atoms ( c>bonic acid %[ ! same t5d5cy to ionize1 or1 s9ce !re is a va/ diff]5ce 9 ! ease ( ionization ( diff]5t acids1 :e!r !re is n also a diff]5ce 9 ! ease ( ionization ( ! diff]5t hydrog5 atoms 9 a polybasic acid4 ,z a matt] ( exp]im5t1 we f9d t a molecule ( c>bonic acid does ionize1 fir/1 & m readily1 into "o hydrog5 ion & an acid c>bonate ion ,,hco#c1 accord+ to ,h#b;,,co#c ,h ,,hco#c4 ,= ?is rev]sible reaction we h#ahd ,h ,,hco#c _/ ,h#b;,,co#c ,k#a4 7#b7 ,! value ( ?is con/ant1#ahe call$ ! prim>y ionization con/ant ( c>bonic acid1 is #j4c;,e#f4 ,! acid c>bonate-ion ,,hco#c1 9 turn1 is ioniz$ to a c]ta9 ext5t1 produc+ ano!r hydrog5 ion & ! c>bonate-ion1 ,,co#cb4 ,we h ,,hco#c ,h ,,co#cb1 & ,h ,,co#cb _/ ,,hco#c ,k#b4 7#c7 ,! value ( ?is con/ant#ahf1 call$ ! con/ant ( ! p#ajb second>y ionization ( c>bonic acid1 is #j4jg;,e#i1 :i* has ab\t "o f\r-?\s&? ( ! value ( ! con/ant = ! prim>y ionization4 ,if we comb9e equations 7#b7 & 7#c7 we h ,h ,,hco#c ,h ,,co#cb _/ 7,h#b;,,co#c ,,hco#c7 ,k#a ,k#b 7#d7 or ,h#b ,,co#cb _/ ,h#b;,,co#c ,k4 ,?is is equation 7#a71 d]iv$ orig9ally by ! application ( ! law ( mass action to ! relation betwe5 ! c>bonate-ion1 ,,co#cb1 ! hydrog5-ion1 & c>bonic acid1 ,h#b;,,co#c4 ,?is relation1 &1 9 p>ticul>1 ! significant squ>+ ( ! conc5tration ( ! hydrog5-ion1 an ion :i* appe>s twice 9 ! equation = ! =mation ( c>bonic acid f c>bonate & hydrog5 ions1 7#b ,h ,,co#cb ,h#b;,,co#c71 may n[ be int]pret$ me*anically 7p4 #ib7 z foll[s3 ,= ! =mation ( c>bonic acid f a c>bonate ion & two hydrog5 ions1 a c>bonate ion mu/ collide & comb9e fir/ ) "o hydrog5 ion1 & ! velocity = ! =mation ( ?is int]m$iate product1 ,,hco#c1 w be proportional to ! 7total7 conc5tration ( ! hydrog5 ions2 ! product1 ,,hco#c1 to =m ,h#b;,,co#c1 mu/ collide & comb9e ) a hydrog5 ion once m1 & ?is comb9ation w proce$ ) a velocity aga9 proportional to ! 7total7 conc5tration ( ! hydrog5 ions4 ,s ! velocity = ! trans=mation ( ,,co#cb into ,h#b;,,co#c w be proportional twice ov] to ! 7total7 conc5tration ( ! hydrog5 ions--z well z1 9 ! usual fa%ion1 to ! conc5tration ( ! c>bonate ions pres5t at any mom5t4 ,x is a g5]al pr9ciple t ! prim>y ionization ( polyval5t acids occurs m readily ?an ! second>y1 & ?is 9 turn m readily ?an ! t]ti>y 7if a ?ird ionizable hydrog5 atom is pres5t 9 ! acid74 ,9 ! case ( phosphoric acid1 = in/ance1 ! prim>y ionization into ! hydrog5-ion & ! dihydrog5-phosphate-ion1 ,h#b,,po#d1 takes place s readily t phosphoric acid reacts /rongly acid#ahg to me?yl orange1#ahh ! p#ajc conc5tration ( hydrog5-ion be+ suffici5tly great to affect ?is indicator 7see ,,exp4 bel[74 ,:5 phosphoric acid is neutraliz$ by "o equival5t ( a base1 say ( sodium hydroxide1 ! salt =m$1 sodium dihydrog5-phosphate1 ,na,h#b,,po#d1 yields sodium-ion & dihydrog5-phosphate-ion1 ,h#b,,po#d4 ,! latt] is ioniz$ some:at into ,h & ! bival5t hydrog5-phosphate-ion1 ,,hpo#db4 ,! ionization ( ! ion ,h#b,,po#d is n[ ! *ief s\rce ( supply ( hydrog5-ion 7! fur!r ionization ( ,,hpo#db is practically negligible "h7 & x is ioniz$ s little t ! solution ( ,na,h#b,,po#d no long] *anges ! color ( me?yl orange 7see ,,exp4 bel[74 ,! solution is1 h[ev]1 acid to ! indicator ph5olph?alen1 :i* is mu* m s5sitive to ! hydrog5-ion & w %[ ! pres5ce ( mu* small] conc5trations ( x ?an w me?yl orange4 ,! addition ( a second equival5t ( sodium hydroxide to ! solution conv]ts ,na,h#b,,po#d into ,na#b;,,hpo#d4 ,?is salt gives sodium-ion & ! hydrog5-phosphate-ion ,,hpo#db1 :i*1 9 turn1 is ioniz$ only v slightly1 produc+ phosphate-ion ,,po#dc1 & aga9 hydrog5-ion4 ,! ionization ( ,,hpo#db is s slight1 h[ev]1 & ! conc5tration ( ! hydrog5-ion1 !re=e1 s m9ute1 t ! solution does n react acid ev5 to ! s5sitive indicator ph5olph?alen4 ,,exp4 ,me?yl orange 7v little7 is add$ to #aj c4c4 ( a #j4a mol> solution ( phosphoric acid & #aj c4c4 ( #j4a mol> sodium hydroxide solution is add$ to ! mixture2 ! color w be f\nd to *ange f ! acid to ! neutral t9t j z ! la/ drop or two ( ! alkali are add$4 ,ph5olph?alen is !n add$ to ! mixture & #aj c4c4 m ( ! #j4a mol> sodium hydroxide solution are requir$ to *ange ! color ( ! mixture to a pron\nc$ p9k 7alkal9e7 t9t4 ,ev5 sulphuric acid1 al?\gh its two hydrog5 atoms are ioniz$ v easily1 mak+ sulphuric acid a /rong acid1 %[s a diff]5ce 9 ! ease ( ionization ( ! two hydrog5 atoms4 ,s9ce ionization1 9 g5]al1 is favor$ by dilution1 we f9d t 9 ! case ( su* a /rong acid ! diff]5ce is mo/ m>k$ 9 m conc5trat$ solutions1 ! small] am\nt ( wat] />t+ ! ionization 9 ! m favor$ direction & produc+ fir/1 *iefly1 hydrog5-sulphate ions1 ,,hso#d4 ,:5 ! solution is dilut$1 ! hydrog5-sulphate ions are to a v consid]able ext5t dissociat$ into sulphate ions & hydrog5 ions4 ,! describ$ *ange 9 ionization c be r\ghly foll[$ ) ! aid ( an insoluble sulphate l b>ium sulphate4 ,b>ium sulphate1 :ile v insoluble 9 wat]1 dissolves 9 r /rong sulphuric acid to =m ! acid sulphate1 ,ba7,,hso#d7b1 ! ,,s#db ion ( ! sulphate be+ m or less suppress$ by unit+ ) hydrog5-ion4 ,we h ! action ,ba,s,o#d ,ba#b ,,s#db & ,ba#b ,,s#db ,h ,,hso#d ,ba#b #b ,,hso#d4 ,if ! solution ( ! acid sulphate is p\r$ into a l>ge volume ( wat]1 b>ium sulphate is imm$iately reprecipitat$1 ! hydrog5-sulphate-ion be+ dissociat$1 9 ! dilute solution1 into hydrog5-ion & sulphate-ion1 ,,s#db1 ^: b>ium salt is s difficultly soluble3 ,ba#b #b ,,hso#d ,ba#b #b ,h #b ,,s#db ,ba,s,o#d #b ,h ,,s#db4 p#ajd ,,exp4 ,f9ely divid$ b>ium sulphate is w>m$ = a mom5t ) a few cubic c5timet]s ( conc5trat$ sulphuric acid 9 a te/ tube1 ! mixture is all[$ to settle1 & "s ( ! cle> acid is c>efully decant$ into a l>ge beak] full ( wat]4 ,x may be add$1 t :ile ! prim>y ionization ( sulphuric acid does n yield an equilibrium con/ant = ! ratio ,h ,,hso#d _/ ,h#b,,s#d1 ev5 su* a /rong acid z is sulphuric acid is f\nd to give a fairly good con/ant#ahi = ,h ,,s#db _/ ,,hso#d4 ,! value ( ?is con/ant#ahi is #j4jc4 ,! ,ionization ,con/ants,a ( ,acids ,acid4 ,equilibrium ,ratio4 ,k4 ,hydro*loric ,h,cl_/,h,cl 7#a7 ,hydrobromic ,h,br_/,h,br 7#a7 ,hydroiodic ,h,i_/,,hi 7#a7 ,nitric ,h,,no#c_/;,,hno#c 7#a7 ,*romic,b ,h,h,cr,o#d_/;,h#b;,cr,o#d 7#a7 ,h,cr,o#db_/;,h,cr,o#d #j4f;,e#f ,sulphuric,c,d ,h,,hso#d_/;,h#b,,s#d 7#a7 ,h,,s#db_/;,,hso#d #j4c;,e#a ,oxalic,e ,h,c#b,o#d_/;,h#b;,c#b,o#d #c4h;,e#b ,h,c#b,o#db_/;,,hc#b,o#d #j4e;,e#d ,phosphoric,f ,h,h#b,,po#d_/;,h#c,,po#d #j4a;,e#a ,h,,hpo#db_/;,h#b,,po#d #j4b;,e#f ,h,,po#dc_/;,,hpo#db #j4d;,e#ab ,ars5ic,d ,h,h#b;,as,o#d_/;,h#c;,as,o#d #j4e;,e#b ,nitr\s,b ,h,,no#b_/;,,hno#b #j4e;,e#c ,acetic,g ,h,,*#c;,,co#b_/;,,*#c;,,co#b;,h #a4h;,e#e ,c>bonic,h,i ,h,,hco#c_/7;,h#b;,,co#c ,,co#b7 #j4c;,e#f ,h,,co#cb_/;,,hco#c #j4g;,e#aj ,h#b,s,j,k ,h,,%_/,h#b,s #j4i;,e#g ,h,s#b_/,,% #j4a;,e#ad ,boric,b ,h,h#b;,,bo#c_/;,h#c;,,bo#c #j4g;,e#i ,hydrocyanic ,h,,cn_/,,hcn #j4g;,e#i ,ars5i\s ,h,h#b;,as,o#c_/;,h#c;,as,o#c #j4f;,e#i ,wat],l,c ,h,,ho_/,h#b,o at #be #j4b;,e#ae at #ajj #j4i;,e#ad ,h,,ho at #be #a4b;,e#ad at #ajj #j4e;,e#aa ,,table ,,notes3 ,a4 ,z expla9$ on p4 #ajj1 ! bracket$ values giv5 = ! /rong acids are n con/ants1 b express ! values ( ! ratios ,h ,anion _/ ,acid = #j4a mol> solutions4 ,b4 ,see ref]5ces1 ,noyes1 ibid41 #cb1 #hfj 7#aiaj74 ,c4 ,noyes & ,ea/man1 ,c>negie ,in/itution ,publications1 #fc1 #bgd 7#aijg74 ,d4 ,lu!r1 ,z4 ,elektro*1 #ac1 #bif 7#aijg74 ,e4 ,*&l] 7,mc,coy71 ,j4 ,am4 ,*em4 ,soc41 #cj1 #gac 7#aijh74 ,f4 ,abbot & ,bray1 ibid41 #ca1 #gfj 7#aiji74 ,g4 ,see above1 p4 #ii4 ,h4 ,walk]1 ,j4 ,*em4 ,soc41 7,london71 #gg1 #e 7#aijj74 ,i4 ,mc,coy1 ,am4 ,*em4 ,j41 #bi1 #dee 7#aijc72 ,/ieglitz1 ,c>negie ,in/itution ,publications1 #ajg1 #bdc 7#aiji74 ,j4 ,au]ba*1 ,z4 phys4 ,*em41 #di1 #bbj 7#aijd74 ,k4 ,knox1 9 ,abegg's laboratory1 ,trans4 ,f>aday ,soc41 #d1 #dc 7#aijh74 ,l4 ,vide p4 #ff4 p#aje ,! diff]5ce 9 ! t5d5cies ( acids to ionize1 z express$ 9 ! table1 may be recogniz$ 9 equival5t solutions by any ( ! prop]ties dep5d5t on ! ionization1 su* z ! conductivity1 ! *emical activity1 ! osmotic pressure & alli$ effects1 & s =?4 ,if ! conductivities ( equal volumes ( equival5t 7e4g4 normal7 solutions ( hydro*loric1 phosphoric & acetic acids are comp>$ 7exp47#aij1 x is readily se5 t hydro*loric acid is ! be/ conductor1 phosphoric acid a mu* poor] "o1 & acetic acid an exce$+ly poor "o 7! conductivity ( normal acetic acid is ab\t #a _/ #bjj t ( normal hydro*loric acid1 & ! conductivity ( normal phosphoric acid is ab\t #a _/ #ad t ( normal hydro*loric acid74 ,s9ce ! conductivity is approximately proportional to ! conc5tration ( ! hydrog5-ion#aia 9 ea* ( ! solutions1 x is evid5t t ! hydro*loric acid is ioniz$ to a consid]ably great] ext5t ?an ei!r ( ! o!r acids--?an acetic acid1 9 p>ticul>4 ,simil>ly1 if a drop 7#j4je c4c47 ( mol> hydro*loric acid & a drop ( mol> acetic acid are add$ to equal volumes 7#ej c4c47 ( a v dilute solution ( me?yl orange 7exp471 ! color w be *ang$ decid$ly by ! hydro*loric acid to a bright p9k1 b by ! acetic acid only to an orange hue4 ,aga91 if a precipitate ( b>ium *romate or calcium oxalate is treat$ ) "s /rong acid1 hydro*loric or nitric1 = in/ance1 x dissolves readily1 :ile a consid]able excess ( acetic acid 7exp47 only dissolves traces ( ei!r precipitate4#aib ,9 ?is way1 ! *emical behavior ( ^! acids diff]s 9 degree1 z a result ( ! diff]5t t5d5cies to ionize1 :i* are express$ 9 ! con/ants ( ! table4 ,advantage is tak51 9 analysis1 ( su* diff]5ces4 ,acetic acid1 = in/ance1 is us$ :5 only a slight degree ( acidity is desir$--z 9 recogniz+ b>ium-ion by its *romate1 or oxalic acid by means ( its calcium salt4 ,hydro*loric or nitric acid is us$ :5 decid$ acidity is requir$--z 9 ! sep>ation ( gr\ps by hydrog5 sulphide 7,*ap4 ,,xi74 ,! ,ionization ( ,bases4--,! same relations hold = bases z = acids3 ! weak] bases give ionization con/ants z p#ajf d ! weak] acids2 ! /rong bases1 aga91 z 0 m5tion$ above1 d n give con/ants4 ,! values = /rong bases1 /at$ 9 ! foll[+ table1 are bracket$1 & ref] to ! ionization 9 #j4a mol> solutions ( ! bases4 ,polyval5t bases1 l polybasic acids1 ionize 9 /ages1 & ! prim>y ionization is usually /rong] ?an ! second>y ionization1 & s =?4 ,= in/ance1 a /udy ( f]ric *loride solution %[s t ! ?ird hydroxide gr\p ( f]ric hydroxide1 ,fe7,,oh7#c1 mu/ h ! smalle/ ionization con/ant4#aic ,! ,ionization ,con/ants,a ( ,bases ,base4 ,ratio4 ,k4 ,potassium hydroxide ,k,,ho_/,,koh 7#a7 ,sodium hydroxide ,na,,ho_/,na,o,h 7#a7 ,b>ium hydroxide ,ba#b;,,ho#b_/;,ba7,,oh7#b 7#j4jc7 ,/rontium hydroxide ,sr#b;,,ho#b_/,sr7,,oh7#b 7#j4jc7 ,calcium hydroxide,b ,ca#b;,,ho#b_/;,ca7,,oh7#b 7#j4jc7 ,ammonium hydroxide,c,d ,,nh#d;,,ho_/ 7,,nh#d,,oh,,nh#c7 #a4h;,e#e ,hydraz9e,e ,n#b;,h#e;,,ho_/ 7,n#b;,h#e,,oh,n#b;,h#d7 #j4c;,e#e ,anil9e,f ,c#f;,h#e,,nh#c;,,ho_/ 7,c#f;,h#e,,nh#c,,oh ,c#f;,h#e,,nh#b7 #j4e;,e#i ,wat] ,h,,ho_/,h#b,o at #be #j4b;,e#ae at #ajj #j4i;,e#ad ,h,,ho at #be #a4b;,e#ad at #ajj #j4e;,e#aa ,,table ,,notes3 ,a4 ,z expla9$ above1 ! bracket$ values "u ,k = /rong bases are n con/ants1 b express ! values ( ! ratios = #j4a mol> solutions only4 7,= ! alkal9e e>?s #j4je mol> solutions are ref]r$ to47 ,b4 ,e/imat$ value4 ,c4 ,vide page #afj4 ,d4 ,correct$ value1 f ,br$ig's data1 ,z4 phys4 ,*em41 #ac1 #cbb 7#ahid74 ,a4 ,a4 ,noyes1 ,c>negie ,in/itution1 ,publication ,no4 #fc1 p4 #agh1 f9ds ! value #ag4c;,e#f = #ah4 ,e4 ,uncorrect$ value1 ,br$ig1 ibid4 ,f4 ,br$ig1 ibid42 ,/ieglitz & ,d]by1 ,am4 ,*em4 ,j41 #ca1 #deg 7#aijd74 ,:ile ! con/ants ( a l>ge numb] ( organic bases#aid h be5 det]m9$ few con/ants ( inorganic bases are z yet kn[n4 ,! fact t ! majority ( inorganic bases are polyval5t & difficultly soluble has made _! exam9ation 9 ?is respect m difficult4 ,f ! /udy ( ! decomposition ( salts by wat] 7see ,*apt] ,x71 ! trival5t bases1 su* z p#ajg f]ric hydroxide & alum9ium hydroxide1 are f\nd to be mu* weak] ?an bival5t bases l cadmium1 z9c & lead hydroxides1#aie b ! data are n suffici5t = ! calculation ( any con/ants1 or = di/+ui%+ betwe5 ! ionization ( ! fir/1 second & ?ird hydroxide gr\ps4 ,! diff]5ce 9 ionization & 9 *emical activity betwe5 a /rong base1 l sodium or potassium hydroxide1 & a weak base1 l ammonium hydroxide1 has already be5 discuss$ & illu/rat$ 7see p4 #gg74 ,9 analysis1 advantage is frequ5tly tak5 ( ^! relations4#aif ,! ,ionization ( ,salts4--,:ile we read & he> a good deal ab\t /rong & weak acids1 & /rong & weak bases1 ! expression /rong or weak salt is nev] he>d2 z a matt] ( fact1 all salts1 ) v few exceptions1 ionize exce$+ly readily--ab\t z readily z ! /ronge/ acids & bases4 ,!re are m9or diff]5ces1 b none ( great mom5t--none ( ! k9d indicat$ by ! wide range ( con/ants = ! acids & bases4 ,!re are only a few important exceptions to ?is g5]al rule--! mo/ important ones1 among ! common salts1 be+ m]curic *loride & m]curic cyanide3 _! exceptional behavior 9 reg>d to ionization1 z indicat$ by _! conductivities 7see bel[71 is f\nd side by side ) an exceptional *emical behavior1 exactly z ! !ory ( ionization w\ld lead u to anticipate1 & x r5d]s necess>y c]ta9 precautions1 p>ticul>ly 9 analytical "w1 :i* w be discuss$ lat] 7,*ap4 ,,vi74 ,ord9>y salts are all ioniz$ readily3 = in/ance1 :]eas acetic acid 9 mol> solution is ioniz$ only to ! ext5t ( #j4cg p] c5t1 its salts are highly ioniz$1 ! degree ( ionization ( sodium acetate1 = example1 be+ #eb4h 9 mol> solution4 ,z 9 ! case ( ! /rong acids & bases1 salts ( ! type ,me,x1 :i* ionize accord+ to ! equation ,me,x ,me ,x & :i*1 accord+ to ! law ( *emical equilibrium1 might be expect$ to give a con/ant ratio ,me,x _/ ,me,x1 d n give a con/ant ratio4 ,t is1 :5 ! values obta9$ = ! conc5trations ( ! ions & ( ! nondissociat$ molecules1 9 solutions ( v>i\s p#ajh /r5g?s1 are sub/itut$ 9 ?is =mula1 diff]5t values are obta9$4#aig ,= potassium *loride1 we h ! foll[+ relations3 ,mol> ,p] c5t ,ratio4 ,conc5tration4 ,conductivity4 ,ioniz$4 #j4 #aca4b #ajj -- #j4jja #abg4f #ig4c #j4jce #j4ja #abb4e #ic4d #j4acj #j4je #aae4i #hh4d #j4cce #j4aj #aaa4i #he4a #j4dhe #j4bj #ajg4g #hb4a #j4ged #j4ej #ajb4c #gg4i #a4ch #a4jj #ih4b #gd4i #b4bc ,! ,ionization ( ,/rong ,electrolytes & ! ,law ( ,*emical ,equilibrium4--,! fact t ! ionization ( good electrolytes does n seem to con=m to ! law ( *emical equilibrium is an exce$+ly important "o--x is1 p]haps1 ! mo/ important problem dem&+ rigor\s inve/igation1 :i* is be=e *emi/s at ! pres5t "t4 ,x has be5 us$ z an argum5t aga9/ ! :ole !ory ( ionization1 & is ! mo/ important objection t has be5 urg$ aga9/ x4 ,b1 to ! imp>tial obs]v]1 ?is s+le discrepancy1 betwe5 obs]vation & :at we might h anticipat$1 w only prove a /rong] /imulus to ke5] inve/igation & to m rigor\s analysis ( relations1 s9ce ! latt] are m complex ?an 0 at fir/ expect$4 ,)\t consid]+ ! mass ( evid5ce 9 favor ( ! !ory1 f\nd 9 o!r fields ( *emi/ry & 9 physics1 a "p ( :i* has be5 giv5 above1 we mu/ rememb] t ?is fundam5tal law ( *emical equilibrium has already decid$ unequivocally 9 favor ( ! !ory 9 hundr$s ( cases ( ! ionization ( weak acids & weak bases#aih & t ^! are ! cases :]e ! conditions are mo/ simple4#aii p#aji ,x w\ld lead too f> f our subject to ent] into a full discussion ( ?is important "q4 ,x w be suffici5t "h to indicate two directions ( inquiry1 :i* promise to lead to an explanation ( ! app>5t contradiction betwe5 ! dem&s ( ! law ( *emical equilibrium & ! ionization ( /rong electrolytes4 ,9 ! fir/ place1 ! law ( *emical equilibrium is bas$ !rmodynamically1 i4e4 f ! po9t ( view ( ! ultimate en]gy relations involv$1 on ! assumption t none b negligible =ces ( attraction or repulsion exi/ betwe5 ! molecules1 ^: conc5trations are factors 9 ! equilibrium equations 7cf4 p4 #ie74bjj ,n[1 9 solutions ( electrolytes ?is condition is n /rictly fulfill$ "u any circum/ances2 ! attractions betwe5 ions ( opposite *>ge & ! repulsions ( ions ( l *>ge1 z well z ! effect ( *>g$ p>ticles on neutral molecules1 come into play4 ,= /rong electrolytes1 :]e ! proportion ( *>g$ p>ticles is always a l>ge "o1 ! deviations f ! simpl] conditions to :i* alone ! law is really applicable mu/ be v mu* great] ?an = weak electrolytes4 ,x is1 !re=e1 probable t ^! electrical =ces#bja are ! s\rce ( ! deviation ( ! ionization ( /rong electrolytes f ! law ( *emical equilibrium3 al?\gh ionization is a rev]sible reaction1 =ces come into play :i* make ! simple law inapplicable1 & x is altoge!r likely1 !re=e1 t we %all f9d1 :5 all ! factors h be5 inve/igat$1 t /rong electrolytes %\ld n & _c obey ?is law alone4#bjb ,9 confirmation ( ?is conclusion1 rec5t c>eful calculations#bjc h %[n t entirely analog\s deviations f ! equilibrium law become p]ceptible 9 r conc5trat$ solutions ( weak electrolytes1 su* z acetic acid1 9 :i* !re is an accumulation ( *>g$ p>ticles1 m ne>ly ak9 to t pres5t 9 dilute solutions ( /rong electrolytes4 ,s x appe>s m & m c]ta9 t ! deviations are a result ( ! pres5ce ( electrically *>g$ compon5ts 9 ! solutions1 ! am\nt ( deviation dep5d+ on _! conc5tration4 ,! ,salt ,effect4--,9 ! second place1#bjd x seems possible t ! pres5ce ( /rong electrolytes 9 a solution may modify ! ioniz+ p[] ( ! solv5t 9 su* a way z to increase x1 & to increase x ! m1 ! m conc5trat$ ! ions are 9 ! solution4#bje ,! ioniz+ p[] ( solv5ts1 z has be5 expla9$1 is intimately connect$ ) _! dielectric prop]ties4 p#aaj ,n[1 solid salts h high] dielectric con/ants ?an has#bjf solid wat]1 & ! dielectric con/ant ( a comp\nd is usually mu* high] 9 ! liquid ?an 9 ! solid =m4#bjg ,x is possible1 !re=e1 t ! pres5ce ( salts 9 ! solution increases ! dielectric or1 at any rate1 ! ioniz+ p[] ( ! solv5t & !re are _m facts :i* w\ld be expla9$ by su* a behavior4 ,un=tunately = any decision ( ! "q1 det]m9ations ( ! dielectric con/ants ( salt solutions h giv5 contradictory results2 ! m rec5t1 & possibly m reliable results ( ,drude#bjh indicate t salt solutions %[ approximately ! same dielectric behavior z wat] itself4 ,smale1 9 ,n]n/'s laboratory1 on ! o!r h&1 obta9$ results indicat+ t salt solutions h decid$ly high] dielectric con/ants ?an pure wat]4#bji ,a f9al decision 9 ! matt] w\ld be ( great importance4#baj ,b1 z expla9$ be=e 7p4 #fd71 !re are o!r prop]ties ( a solv5t :i* seem to be intimately relat$ to its ioniz+ p[] & :i* may be modifi$ by ! pres5ce ( salts1 i4e4 ( /rong electrolytes4 ,! value obta9$ = ! proportion ,me ,x _/ ,me,x gr[s rapidly ) increas+ conc5tration1 indicat+ a disproportionately l>ge ionization 9 ! m conc5trat$ solutions--:i* is :at "o w\ld expect1 if electrolytes or _! ions 9 "s way increas$ ! ioniz+ p[] ( ! m$ium4 ,9 agreem5t ) su* a conclusion1 ,arrh5ius f\nd#baa t ! ionization ( weak acids1 l acetic acid1 is increas$ by ! pres5ce ( =eign neutral salts1 su* z sodium *loride4 ,?is means1 ( c\rse1 t ! /r5g? ( acetic acid1 z an acid1 is increas$ likewise4 ,,exp4 #j4e c4c4 ( #j4a mol> acetic acid is add$ to #ajj c4c4 ( a dilute solution ( me?yl orange 9 ea* ( ?ree te/ glasses4 ,:5 "s solid sodium *loride 7#c grams1 & !n #c grams m--altoge!r #j4a mole7 is add$ to ! "o solution1 a pla9 increase 9 ! int5sity ( ! acid t9t is obs]v$4#bab ,! addition ( cane sug> to a second solution has no su* effect4 ,! addition ( sodium *loride to a f\r? portion ( ! me?yl orange1 to :i* no acetic acid has be5 add$1 %[s t its color rema9s un*ang$3 ! effect on ! indicator 9 ! fir/ case1 !n1 is ! result ( ! action ( ! salt on ! acetic acid4#bac p#aaa ,! s-call$ salt-effect on ! ionization ( ammonium hydroxide may be illu/rat$ 9 a simil> way4 ,,exp4 #j4e cc ( #j4a mol> ammonium hydroxide is add$ to ea* ( two portions 7#ajj c4c47 ( a dilute solution ( ph5olph?alen4 ,:5 "s sodium *loride solution is !n add$ to "o ( ! two portions1 ! basicity ( ! solution is di/9ctly increas$4 ,! addition ( sodium *loride to a ?ird portion ( ! ph5olph?alen solution %[s t its own reaction to ! indicator is neutral4 ,if ! ioniz+ p[] ( a solv5t is *ang$ by ! pres5ce ( an electrolyte1 !n ! law ( *emical equilibrium1 9 its simple =m1 w\ld n apply to ! ionization ( su* electrolytes 9 v>y+ conc5trations--z little z we %\ld expect to obta9 ! same con/ant = acetic acid 9 aque\s solution & 9 alcoholic solution1 ! ioniz+ p[] ( alcohol be+ mu* small] ?an t ( wat]4 ,! deviation f ! law1 naturally1 w\ld be mo/ m>k$ 9 ! case ( ^? electrolytes :i* ionize s easily z readily to produce high conc5trations ( ions4 ,x may be said t laws bas$ on ! electrical prop]ties ( salt solutions seem to be ! pr$om9at+ laws gov]n+ ! ionization ( electrolytes & modify+1 9 c]ta9 cases1 ! *emical laws bas$ on ! /udy ( non-electrolytes4#bad ,= ! purposes ( qualitative analysis1 x w suffice to be> 9 m9d ! fact t ! ionization#bae ( salts1 /rong acids & /rong bases does n con=m to ! laws ( mass action1 & ! fact t practically all salts 7) ! notable exceptions1 among common salts1 giv5 on p4 #ajg7 are v readily ioniz$ 9 aque\s solution1 namely to ! ext5t ( #dj to #he 9 solutions ( su* mod]ate conc5tration z #j4a mol>4#baf ,"s ,applications ( ! ,law ( ,*emical ,equilibrium4--,accord+ to ! discussions giv5 above1 = ! ionization ( acetic acid1 ,,*#c;,,co#b;,h ,,*#c;,,co#b ,h we h ! relation ,,*#c;,,co#b ,h _/ ,,*#c;,,co#b;,h ,kionization4 p#aab ,if ! conc5trations ( ! compon5ts are modifi$ 9 any way1 ! condition ( equilibrium is di/urb$ & *ange w result1 always t[>d ! re/oration ( equilibrium4 ,! *anges1 9 ! case ( purely ionic actions1 are f\nd to take place ) an enorm\s velocity1 equilibrium be+ re/or$ almo/ in/antly4 7#a7 ,if ! solution ( acetic acid1 repres5t$ 9 ! above equation1 is dilut$ by an equal volume ( wat]1 ! condition ( equilibrium is di/urb$3 ,,*#c;,,co#b ,h _/ 7 ,,*#c;,,co#b;,h7 ,kionization4 ,! ratio is small] ?an t requir$ = equilibrium1 & !re w be a *ange t[>ds increas+ ! ratio4 ,! acid w ionize m rapidly ?an x w be =m$ f ! acetate & hydrog5 ions 7:i* collide less frequ5tly 9 ! dilut$ solution7 & a new condition ( equilibrium w be rea*$1 :5 m ( ! acid is ioniz$4 ,we f\nd1 z a matt] ( fact1 t ! m a solution ( acetic acid is dilut$1 ! l>g] is ! proportion ( ioniz$ acid 7see p4 #ii74 7#b7 ,if ! conc5tration ( ! acetate-ion is increas$ 9 ! solution by ! addition ( a salt ( acetic acid1 say sodium acetate1 we h x ,,*#c;,,co#b ,h _/ ,,*#c;,,co#b;,h ,kionization4 ,! ratio is l>g] ?an all[$ by ! equilibrium law1 & ! acetate ions w comb9e ) ! hydrog5 ions to =m acetic acid m rapidly ?an ! ions are =m$ f x1 until equilibrium is re/abli%$4 ,9 a mol> solution ( acetic acid1 #j4db ( ! acid is ioniz$1 & we h ,,*#c;,,co#b ,h _/ ,,*#c;,,co#b;,h #j4jjdb #j4jjdb _/ #j4iieh #a4h;,e#e4 ,if an equival5t quantity ( sodium acetate %\ld be add$1 i4e4 "o mole or #hb grams ( ! salt p] lit]1 ! salt be+ ioniz$ to ! ext5t ( #ec1 we w\ld h #j4ecd #j4jjdb _/ #j4iieh #a4h;,e#e4 ,! equilibrium con/ant w be satisfi$ 7& ! velocity ( ionization ( ! acetic acid w become equal to ! velocity ( its p#aac =mation f its ions7 :5#bag ,,*#c;,,co#b #j4ec1 ,h #j4jjj1jcd & ,,*#c;,,co#b;,h #j4iii1iff4 ,if we use two *>act]i/ic places 9 ! decimals1 we h 7#j4ec #j4jjjjcd7 _/ #a #a4h;,e#e4 ,! mo/ significant fact 9 ! new condition ( equilibrium is ! extremely small conc5tration ( hydrog5-ion 9 ! solution4 ,s9ce ! acid prop]ties ( acetic acid are due to its =m+ hydrog5-ion1 we w\ld conclude t su* prop]ties ( acetic acid are v mu* weak5$ by ! pres5ce ( its own salts4 ,?is conclusion has be5 fully v]ifi$ by c>eful quantitative measurem5ts & c be demon/rat$ z foll[s#bah3 ,,exp4 ,to two ( ?ree portions ( a dilute solution ( me?yl orange equal quantities ( acetic acid are add$ 7e4g4 #j4e c4c4 mol> acid71 ! ?ird portion be+ res]v$ to %[ ! color ( ! neutral solution ( ! indicator4 ,n[1 if into "o ( ! solutions1 to :i* acetic acid has be5 add$1 a few cry/als ( sodium acetate are gradually dropp$1 ! color rev]ts gradually to ! color ( ! orig9al neutral solution2 ! conc5tration ( hydrog5-ion becomes s small1 t x does n visibly affect ?is indicator1 :i* is n v s5sitive to acids1 7,h74#bai ,! solution1 accord+ to ! views express$1 %\ld /ill be v slightly acid1 & by ! use ( an indicator 7litmus pap]7 :i* is mu* m s5sitive to ! hydrog5-ion ?an is me?yl orange1 no difficulty is f\nd 9 recogniz+ ?is fact also4 ,z a matt] ( exp]im5t1 !n1 an acid l acetic acid is v mu* weak] 9 ! pres5ce ( its own salts ?an 9 _! abs5ce1 & ! equilibrium con/ant & ! conc5trations ( ! compon5ts us$ det]m9e ! ext5t to :i* ! hydrog5-ion is suppress$4 ,! same mu/ be true = all weak acids & simil> relations mu/ p#aad hold = all weak bases#bbj--;9 g5]al1 weak acids & weak bases are v mu* weak5$ by ! addition ( _! own salts4 ,! importance ( recogniz+ su* *anges1 9 consid]+ analytical reactions1 may be illu/rat$ z foll[s3 ,,exp4 ,a solution ( f]r\s acetate 7f]r\s *loride ) an equival5t quantity ( sodium acetate7 is treat$ ) hydrog5 sulphide2 a precipitate ( black f]r\s sulphide is =m$4 ,a second portion ( ! solution is fir/ decid$ly acidifi$ ) acetic acid3 hydrog5 sulphide does n precipitate any f]r\s sulphide4 ,"s cry/als ( sodium or ammonium acetate are add$ to ! mixture & a black precipitate ( iron sulphide imm$iately appe>s ar\nd ! salt z x dissolves1 & on mix+ ! cont5ts a heavy precipitate ( ! sulphide ?r\gh\t ! vessel is =m$4 ,x is evid5t t ! addition ( a neutral salt1 conta9+ ! same negative ion z ! add$ acid1 may completely rev]se ! net result ( a te/ ) hydrog5 sulphide4 7#c7 ,if ! conc5tration ( ! hydrog5 ions 9 ! solution ( acetic acid is increas$ by ! addition ( hydro*loric1 or "s o!r /rong acid1 equilibrium betwe5 ! acetic acid & its ions w likewise be di/urb$ & ! new condition ( equilibrium w %[ a suppression ( ! acetate-ion4 ,in/ances ( su* action ( a /rong acid 9 suppress+ ! *>act]i/ic ions ( weak] acids w be discuss$ 9 detail 9 connection ) ! analytical applications ( hydrog5 sulphide 7,*ap4 ,,xi71 :]e ! action is ( peculi> importance4 ,/rong bases h a simil> effect on weak bases4 7#d7 ,if "o ( ! ions ( acetic acid is suppress$ by ! addition ( "s ag5t1 equilibrium is aga9 de/roy$ & ! result+ *ange is always 9 ! direction ( re/abli%+ a condition ( equilibrium on ! basis ( ! law ( equilibrium4 ,in/ances ( ?is common case1 su* z ! neutralization ( acetic or any o!r acid by a base1 or ! driv+ out ( a weak acid1 f its salts1 by a /rong acid1 or ( a weak base by a /rong base1 consid]$ f ! po9t ( view ( ! equilibrium law1 %\ld be work$ out by ! /ud5t4#bba p#aae 7#e7 ,! displacem5t ( an acid 7or base7 9 salts by ano!r acid 7or base7 is subject always to ! law t equilibrium is rea*$1 :5 all ! equilibrium con/ants are satisfi$ 9 ! sy/em4 ,v frequ5tly1 ! application ( ! law w lead1 app>5tly1 to ! incorrect conclusion t ! /rong] acid 7or base7 w always displace1 m or less completely1 ! weak]#bbb--;an inf]5ce1 out ( :i* grew1 inde$1 ! *>act]ization ( acids & bases z /rong & weak4 ,yet1 :5 ! laws ( equilibrium1 z ! result ( ! peculi> values ( con/ants1 dem& t1 on ! contr>y1 a /rong acid or base %\ld be displac$ by a weak1 or ev5 a feeble "o1 we f9d t ! *ange 9 ?is direction occurs ) equal ease4 ,num]\s in/ances w be giv5 :]e a weak acid 7or a weak base7 does ?is to a c]ta9 ext5t 7,*ap4 ,x71 & o!rs :]e precipitation ( salts facilitates ! action ( weak] acids greatly by ! introduction ( new1 physical con/ants4 ,! foll[+ case ( ! lib]ation ( hydro*loric acid by ! exce$+ly weak acid1 hydrocyanic acid1 is important because x %[s a rev]sal ( ! common action )\t ! =mation ( any precipitate1 & especially because x br+s out mo/ /rik+ly ! relations betwe5 ionization & *emical activity 9 a case ( special importance to analytical *emi/s4 ,! ,exceptional ,ionization ( ,m]curic ,cyanide & ,its ,consequ5ces4--,we h f\nd t practically all salts are v readily ioniz$4 ,b x 0 m5tion$ t !re are a few exceptions to ?is rule1 & m]curic *loride & especially m]curic cyanide 7 nam$ z ! mo/ important exceptions f ! po9t ( view ( analytical *emi/ry4 ,! diff]5ce 9 ionization betwe5 ^! two salts & ord9>y salts may be %[n readily by ! app>atus previ\sly us$ to demon/rate ! diff]5ce 9 ! ionization ( v>i\s bases & acids4 ,,exp4 ,into ! p>allel tubes ( ! conductivity app>atus 7p4 #gg7 equival5t quantities#bbc ( solutions ( m]curic cyanide#bbd ,hg7,,cn7#b1 m]curic *loride p#aaf ,hg,cl#b1 & b>ium *loride ,ba,cl#b1 are introduc$4 ,! b>ium *loride repres5ts an ord9>y salt ( ! same type z ! m]cury salts1 & ! curr5t pass+ ?r\gh its solution makes ! little lamp gl[4 ,! electrodes 9 ! m]curic *loride solution mu/ be br\ght q close toge!r be=e suffici5t curr5t w pass ?r\gh ! solution to br+ its little lamp to r$ness4 ,9 ! case ( ! cyanide we c1 at mo/1 get a fa9t1 dull gl[ by br++ ! electrodes toge!r z closely z we c1 )\t all[+ !m to t\* ea* o!r & %ort-circuit ! curr5t4 ,x is evid5t t ^! m]cury salts are n z readily ionizable z are ord9>y salts4 ,?is diff]5ce1 z may be anticipat$1 %[s itself also 9 ! *emical behavior ( _! solutions & makes necess>y special precautions on ! "p ( ! analy/ 9 exam9+ m]cury comp\nds4 ,= in/ance1 :]eas m]curic oxide is readily precipitat$ by ! addition ( sodium hydroxide to solutions ( ! nitrate & ev5 ( ! mod]ately ioniz$ *loride1 "o fails to get a precipitate ( oxide f ! cyanide solution 7exp471 & if we reli$ on ?is te/1 we %\ld ov]look ! m]cury entirely4 ,t traces ( ! m]curic-ion are pres5t1 z indicat$ by ! m9imal conductivity ( ! cyanide1 is confirm$ by ! fact t f ! cyanide solution ! sulphide1 :i* is mu* less soluble ?an is ! oxide1 may be precipitat$ by ! addition ( ammonium sulphide 7exp474 ,t ! sulphide is 9 fact less soluble#bbe ?an ! oxide is %[n by ! conv]sion ( ! latt] into ! =m] by ! action ( ammonium sulphide 7exp474 ,z a fur!r result ( ! abnormally slight ionization ( ^! m]cury salts1 ! analy/1 unless he is on 8 gu>d1 may also h difficulty 9 discov]+ ! pres5ce ( _! negative ions4 ,?us1 :ile sodium *loride readily gives hydrog5 *loride :5 treat$ ) conc5trat$ sulphuric acid1 m]curic *loride1 al?\gh x is a soluble salt1 does n 7exp471 & reliance on ?is te/ alone might lead to a gross error4#bbf ,9 ! case ( ! cyanide1 x is correspond+ly difficult to recognize ! p#aag cyanide-ion 7see ! laboratory exp]im5t1 ,"p ,,iii74 ,! ord9>y te/s fail to %[ its pres5ce until ! m]cury has be5 remov$ f ! solution by precipitation z a sulphide4 ,m]curic cyanide be+ a deadly poison :i* analy/s are liable to meet & h met ) 9 crim9al cases1 x is cle> t a k ( ^! facts is vital to analytical accuracy4 ,n[1 ! v slight ionization ( m]curic cyanide enables u to realize1 9 ! foll[+ exp]im5t1 ! case :]e an exce$+ly weak acid )\t ! =mation ( any precipitate involv+ physical con/ants1 may displace a mu* /rong] acid f its salts4 ,hydrocyanic acid is "o ( ! weake/ acids 7table1 p4 #ajd71 ! con/ant = ! ratio ,h ,,cn _/ ,,hnc be+ #j4g;,e#i4 ,x is s weak an acid t ! addition ( a dilute solution to me?yl orange w n r$d5 ! indicator1 b w h only a b>ely p]ceptible effect on x 7exp474 ,m]curic *loride solutions also are almo/ neutral to me?yl orange 7exp47 7v slight decomposition ( ! salt by wat] makes ! solution v slightly acid1 n en\gh to produce m ?an an orange color ) me?yl orange74 ,n[1 m]curic *loride1 :ile x is n v easily ioniz$1 is1 we f\nd1 v mu* m readily ioniz$ ?an is m]curic cyanide4 ,! consequ5ce is t :5 we add hydrocyanic acid to a m]curic *loride solution1 ! equilibrium betwe5 m]curic *loride & its ions & betwe5 hydrocyanic acid & its ions w be decid$ly displac$1 ! m]curic-ion comb9+ ) ! cyanide-ion to =m ! sc>cely ionizable m]curic cyanide4 ,z a result1 m & m ( ! molecul> m]curic *loride & hydrocyanic acid w be ioniz$2 & s9ce ! o!r ions1 ! *loride & ! hydrog5 ions1 =m a readily ionizable electrolyte1 hydro*loric acid1 ^! ions 7,h & ,cl7 w accumulate 9 ! solution & we %all h suffici5t ioniz$ hydro*loric acid lib]at$ to make ! solution decid$ly acid4 ,,exp4 ,:5 ! two solutions describ$ above are mix$1 a /rongly acid solution1 color$ a bright p9k1 results4 ,9 ! foll[+ equations ! d>k arr[s indicate ! direction 9 :i* ! action goes :5 ! solutions are mix$3 ,hg,cl#b ,hg#b #b ,cl #b ,,hcn #b ,,cn #b ,h #b ,,cn ,hg#b ,hg7,,cn7#b #b ,cl #b ,h #b ,h,cl ,,footnotes3 #aff ,conc5trations are usually measur$ 9 moles or gram-molecul> weights p] lit]1 & a gram-molecul> or mol> weight ( a comp\nd is its molecul> weight express$ 9 grams4 ,h5ce ! numb] ( grams ( a giv5 sub/ance 9 a lit] divid$ by its molecul> weight repres5ts its conc5tration4 #afg ,n]n/1 ,!oretical ,*emi/ry1 #dbc1 #dcc2 ,o/wald1 ,lehrbu*1 ,,ii#b1 #ajd1 etc41 #bif2 ,walk]1 ,introduction to ,physical ,*emi/ry 7#aiji71 #bei1 etc4 #afh ,n e collision ( a molecule ( ,a ) "o ( ,b is suppos$ to result 9 a *emical int]action1 b ! numb] ( collisions ) su* a result is consid]$ to be directly proportional to ! total numb] ( collisions4 ,van 't ,h(f1 ,lectures on ,physical ,*emi/ry1 ,i1 #ajd4 #afi ,s9ce 9 any *emical action1 :i* has n rea*$ a condition ( equilibrium1 ! conc5trations ( ! react+ sub/ances *ange cont9u\sly1 ! relation betwe5 ! velocity ( ! action & ! conc5trations1 = any mom5t1 is f\nd by ! application ( ! calculus to ! exp]im5tal data4 7,cf4 ,elem5ts ( ,calculus1 by ,"y & ,l9eb>g] 7#aijj71 #afh1 #aha1 #bdj2 ,mellor1 ,high] ,ma!matics = ,/ud5ts ( ,*emi/ry & ,physics 7#aijb71 #aig47 #agj ,n]n/1 loc4 cit41 #eda1 etc42 ,o/wald1 loc4 cit41 #ajg1 etc42 ,walk]1 loc4 cit41 #beg2 ,smi?1 loc4 cit41 #bej1 & #ahj 7,/ud474 #aga ,if a compon5t takes "p m ?an once 9 ! action1 its conc5tration is rais$ to ! p[] correspond+ to ! coeffici5t express+ ! numb] ( its molecules tak+ "p 9 ! action4 ,= in/ance1 = ,a #b ,b ,c ,d1 v#a k#a ,a ,b#b2 7see bel[74 #agb ,cf4 ,van 't ,h(f1 loc4 cit41 ,i1 #bjf4 #agc ,! conc5trations are calculat$ f ! data giv5 by ,bod5/e91 ,z4 phys4 ,*em41 #bb1 #af 7#ahig74 7,cf4 ,van 't ,h(f loc4 cit41 ,i1 #aaj47 #agd ,! fundam5tal mean+ ( ! law is mo/ accurately def9$ 9 !rmodynamic t]ms1 t is1 9 t]ms ( ! "w or en]gy relations connect$ ) *anges ( gase\s or osmotic pressures4 #age ,van 't ,h(f1 loc4 cit41 ,i1 #ajd1 #aei1 etc4 #agf ,9 reg>d to ! v>iations ( ! equilibrium con/ant ) *anges ( temp]ature & ! relations :i* gov]n ^! *anges see ,smi?'s ,inorganic ,*emi/ry 7#aiji71 p4 #bfj4 #agg ,! limitations are indicat$ 9 ! prec$+ section4 #agh ,/ieglitz1 ,am4 ,*em4 ,j41 #bc1 #djf 7#aijj74 #agi ,vide ,/ieglitz1 loc4 cit4 #ahj ,! table is bas$ on ! results ( ,noyes & ,coop]1 giv5 9 ,! ,electrical ,conductivity ( ,aque\s ,solutions1 ,c>negie ,in/itution ,publications1 ,no4 #fc1 pp4 #ach1 #ada 7#aijg74 #aha ,o/wald ,z4 phys4 ,*em41 #b1 #bgh 7#ahhh71 0 ! fir/ to develop ?is relation f ! conductivity data = s-call$ weak acids1 & ! law ( *emical equilibrium1 hold+ 9 su* & simil> cases1 is (t5 call$ ,o/wald's ,law ( ,dilution4 #ahb ,! equilibrium ratio1 us$ z an illu/ration 9 ! text1 is ! equilibrium ratio = monobasic acids4 ,= polybasic acids1 ! ratio w\ld h ! =m dem&$ by ! rule giv5 p4 #id4 ,= in/ance1 = ,h#b,x #b ,h ,x#b1 ! expression ,h#b ,x#b _/ ,h#b,x %\ld be con/ant1 provid$ ! ionization occurs accord+ to ! law ( *emical equilibrium 9 its simple/ t]ms4 ,9 po9t ( fact1 = /rong acids1 ?is ratio holds z little z does ! equilibrium ratio = ! monobasic acids4 #ahc ,ow+ to ! in/ability ( c>bonic acid1 :i* breaks d[n into c>bon dioxide & wat] 7,h#b;,,co#c ,h#b,o ,,co#b71 ! c>bonic acid is1 9 turn1 9 equilibrium ) ! c>bon dioxide4 ,= ! sake ( simplicity1 ?is relation is n includ$ 9 ! detail$ discussion1 & :]ev] ! symbols ,h#b;,,co#c & ,h#b;,,co#c are us$1 !y are int5d$ to repres5t ! total c>bonic acid1 pres5t z su* & z c>bon dioxide4 ,! detail$ discussion ( ! complication m5tion$ w be giv5 9 connection ) ! analog\s case ( ammonium hydroxide & ammonia1 &1 z w be %[n !re1 ) ! significance j atta*$ to ! symbols1 ! relations develop$ 9 ! text are a rigor\s expression ( ! facts4 #ahd ,h1 9 all ! equations us$1 repres5ts z usual1 ! total conc5tration ( hydrog5-ion4 #ahe ,walk] & ,cornack1 ,j4 ,*em4 ,soc4 7,london71 #gg1 #bj 7#aijj74 #ahf ,mc,coy1 ,am4 ,*em4 ,j41 #bi1 #dcg 7#aijc72 ,/ieglitz1 ,c>negie ,in/itution ,publications1 ,no4 #ajg1 p4 #bde 7#aiji74 #ahg ,9 a solution ( phosphoric acid1 all ! possible =ms ( ionization1 describ$ 9 ! text1 occur simultane\sly1 b ! second>y & t]ti>y =ms ( ionization1 z f> z ! conc5tration ( ! hydrog5-ion is conc]n$1 are entirely subord9ate to ! prim>y ionization4 #ahh ,vide footnote1 p4 #gi4 #ahi ,lu!r1 ,z4 ,elektro*em41 #c1 #bif 7#aijg74 ,noyes & ,ea/man1 ,c>negie ,in/itution ,publications1 #fc1 #bgd 7#aijg74 ,noyes & ,/ew>t1 ,j4 ,am4 ,*em4 ,soc41 #cb1 #aacc 7#aiaj74 #aij ,! app>atus describ$ on p4 #gg is us$4 ,vide ,noyes & ,blan*>d1 loc4 cit4 #aia ,hydrog5 ions move five to t5 times z fa/ z ! anions & c>ry #hj-ij p] c5t ( ! curr5t2 see p4 #ef4 #aib ,! solution ( ^! salts is due to ! action ( hydrog5 ions on _! anions2 see ,*ap4 ,,viii4 #aic ,goodw91 ,z4 phys4 ,*em41 #ba1 #a 7#ahif74 #aid ,see ,kohlraus* & ,holborn1 loc4 cit41 p4 #aid4 ,_! values = ,k 7la/ column7 mu/ be divid$ by #ajj to express ! con/ants 9 t]ms ( ! same units z ^? us$ 9 ! above table4 #aie ,j4 ,h4 ,long1 ,j4 ,am4 ,*em4 ,soc41 #ah1 #fic 7#ahif74 ,ley1 ,z4 phys4 ,*em41 #cj1 #cbb 7#ahii72 ,brun]1 ibid41 #cb1 #acc 7#aijj72 ,walk]1 ,j4 ,*em4 ,soc41 7,london71 #fg1 #ehe 7#ahie74 #aif ,in/ances are f\nd 9 ! laboratory exp]im5ts1 ,p>ts ,,iii & ,,iv4 #aig ,! ionization ( salts ( o!r types1 e4g4 ,me,x#b1 ,me#b,y1 etc41 likewise fails to con=m to ! law ( *emical equilibrium4 #aih ,see bel[ 7pp4 #aab-d71 also1 fur!r1 confirmatory evid5ce1 d]iv$ f ! application ( ! same law to ! influ5ce ^u ! degree ( ionization ( weak acids & weak bases1 ex]t$ by ! pres5ce ( _! own salts4 #aii ,see bel[1 9 reg>d to evid5ce t ! di/urb+ factors1 pr$om9ant ) /rong electrolytes1 are exhibit$ 9 mu* slight]1 b p]ceptible measure 9 ! case ( ! weak electrolytes4 #bjj ,see also ! int]pretation ( ! law ( *emical equilibrium f ! viewpo9t ( ! k9etic !ory1 ,n]n/1 ,!oretical ,*emi/ry1 p4 #dbh4 #bja ,= a m detail$ discussion ( ^! views1 see ,lehfeldt's ,electro*emi/ry 7#aijd71 pp4 #gh1 #gi4 #bjb ,v>i\s empirical laws1 express+ ! behavior ( /rong electrolytes1 h be5 sugge/$3 see ,n]n/1 ,!oretical ,*emi/ry1 p4 #dih1 z to ,rudolphi's & van 't ,h(f's rules2 see also ,a4 ,a4 ,noyes1 ,report ( ! ,congress ( ,arts & ,sci5ce1 ,,iv1 p4 #caf 7#aijd74 #bjc ,wegs*eid]1 ,z4 phys4 ,*em41 #gj 7,i71 #fjc 7#aiji74 #bjd ,x is possible t ?is effect is only ano!r =m ( express+ ! v relation discuss$ 9 ! prec$+ p>agraph4 #bje ,arrh5ius1 ,z4 ,elektro*em41 #f1 #aj 7#ahii72 ,z4 phys4 ,*em41 #ca1 #aig 7#ahii74 #bjf ,salts h con/ants av]ag+ ab\t #g1 & runn+ f #e to #bh2 ! con/ant = ice is ab\t #c4 ,l&olt1 ,br/e91 ,mey]h(f]1 ,tabell51 p4 #gff 7#aije74 #bjg ,we h3 ,ice1 #c1 wat] 7at #j71 #hj2 glacial acetic acid1 #b4h1 acetic acid 7liquid71 #aj2 cane sug>1 #d1 cane sug> 9 aque\s solution 7#dj71 #fg4e1 7#f4e71 #de4c4 ,ibid4 #bjh ,z4 phys4 ,*em41 #bc1 #bhj 7#ahig74 #bji ,wi$emann's ,ann41 #fj1 #fbe 7#ahig74 #baj ,see ,wald51 ,z4 phys4 ,*em41 #fa1 #fcf 7#aijh71 9 reg>d to ! difficulties ( ! problem4 #baa ,loc4 cit4 #bab ,cf4 ,szyszk[ski1 ,z4 phys4 ,*em41 #eh1 #dbj 7#aijg74 #bac ,arrh5ius made a calculation ( ! effect1 tak+ into acc\nt all ! r involv$ *anges produc$ by ! salt4 ,loc4 cit4 #bad ,= in/ance1 ! pr9ciple ( isohydric solutions1 discov]$ by ,arrh5ius1 has be5 e/abli%$ empirically & x involves relations :i* are 9 m>k$ disagreem5t ) ! dem&s ( ! law ( *emical equilibrium4 ,vide ,a4 ,a4 ,noyes1 ,report ( ! ,congress ( ,arts & ,sci5ces1 ,,iv1 p4 #cah 7#aijd74 #bae ,! mo/ reliable e/imates ( ! conc5trations ( ions 9 ^! solutions are bas$ on det]m9ations ( ! degrees ( ionization by means ( conductivity measurem5ts 7see ,*ap4 ,,iv1 & ! previ\s footnote74 #baf ,salts ,me,x ionize m readily 7#hj-he 9 #j4a mol> solution7 ?an d salts ,me,x#b or ,me#b,x 7#ej to #gj 9 #j4a mol> solution71 & ^!1 aga91 m readily ?an salts ,me,x 7ab\t #dj 9 #j4a mol> solution74 #bag ,! calculation ( ! condition ( equilibrium c be made1 ) suffici5t accuracy = our purpose1 z foll[s3 ,! d5om9ator #j4iieh 9 ! orig9al proportion1 be+ ne> its limit 7its highe/ possible value is #a 9 a mol> solution71 _c *ange appreciably4 ,consequ5tly1 :5 ! "o factor 9 ! num]ator1 ,,*#c;,,co#b1 is made #j4ec _/ #j4jjdb1 or #abf times z l>ge z x 01 ! o!r factor1 ,h1 to ma9ta9 a con/ant proportion1 mu/ be made #a _/ #abf? ( its orig9al value & #j4jjdb _/ #abf #j4jjj1jcd4 ,= m exact "w1 ! new conc5trations ( ! ?ree compon5ts may be f\nd by solv+ a simple quadratic equation4 #bah ,k/]1 ,z4 fr ,elektro*em41 #d1 #aaj 7#ahig74 #bai ,see note1 p4 #gi4 #bbj ,see ,"p ,,iii = ! application ( ?is pr9ciple to ammonium hydroxide & its exp]im5tal confirmation4 7,cf4 ,arrh5ius1 ,z4 phys4 ,*em41 #b1 #bh 7#ahhh72 ,/ieglitz1 ,am4 ,*em4 ,j41 #bc1 #djf 7#aijj747 #bba ,= in/ance1 9 ! fir/ place1 ! action ( #j4a mole ( ,h,cl on #j4a mole ( ,c#b;,h#c,o#b,na1 dissolv$ 9 a lit] ( wat]1 &1 9 ! second place1 ! action ( #j4a mole ( ,na,o,h on #j4a mole ( ,,nh#d;,cl1 9 a lit] ( wat]1 may be consid]$4 ,! /rong electrolytes 7,h,cl1 ,c#b;,h#c,o#b,na1 ,na,cl1 ,,nh#d;,cl1 ,na,o,h7 may be tak5 to be 7r\ghly7 #hj ioniz$4 ,f ! conc5trations giv5 & ! con/ants involv$1 ! direction & ! presumable int5sity ( ! ma9 *ange 9 ea* ( ! two cases %\ld be det]m9$4 #bbb ,in/ances ( su* displacem5t are giv5 9 ! footnote ( ! previ\s p>agraph4 #bbc ,e4g4 #ej c4c4 ( #j4b mol> solutions4 #bbd ,m]curic cyanide & m]curic *loride are l>gely pres5t 9 aque\s solution z ,hg7,,cn7#bb & ,hg,cl#bb2 see ,*ap4 ,,xii4 #bbe ,see ,*apt] ,,viii 9 reg>d to ?is pro( t m]curic sulphide is less soluble ?an m]curic oxide & 9 reg>d to ! "q h[1 by a cont9u\s di/urbance ( ! equilibrium conditions1 all ! m]cury may be precipitat$ f ! cyanide solution z ! sulphide1 9 spite ( ! v slight degree ( ionization ( ! cyanide4 #bbf ,! *loride is1 h[ev]1 suffici5tly ioniz$ to make possible ! precipitation ( ! v insoluble silv] *loride1 :5 silv] nitrate is add$ to its solution4 p#aah ,,*apt] ,,vii ,,physical ,,or ,,het]og5e\s ,,equilibrium4--,,! ,,colloidal ,,condition ,! law gov]n+ physical or het]og5e\s equilibrium applies to all cases :]e1 at a con/ant temp]ature1 "o & ! same *emical sub/ance is pres5t 9 two or m physical conditions1 or phases1 9 contact & 9 equilibrium ) ea* o!r4 ,we h1 = in/ance1 ! common case ( a liquid1 say wat]1 9 contact ) its vapor1 or ! liquid 9 contact ) its solid phase 7ice7 & its vapor2 or1 we may h a gas1 say oxyg51 9 contact ) its solution 9 "s solv5t l wat]4 ,we may h a solid1 l cane sug>1 9 contact ) its solution4 ,we may also h a sub/ance l brom9e1 :i* is soluble bo? 9 *lor(orm & 9 wat]1 pres5t 9 bo? solutions at ! same "t1 ! two solutions be+ 9 contact b immiscible4 ,^! cases repres5t ! mo/ common types ( sy/ems to :i* ! law ( physical equilibrium may be appli$1 al?\gh ! li/ has by no means be5 exhau/$4 ,! law ( physical or het]og5e\s equilibrium /ates t :5 "o & ! same *emical comp\nd is pres5t 9 two physical /ates or phases1 z express$ 9 ! equation ,s#a ,s#b1 !n :5 equilibrium is rea*$1 at a giv5 temp]ature1 ! ratio ( ! conc5trations ( ! sub/ance 9 ! two phases is "s con/ant numb]3 ,s#a 3 ,s#b k4 ,! bracket$ symbols d5ote conc5trations4 ,x %\ld be not$ t ! condition ( equilibrium is indep5d5t ( ! total quantity#bbg ( sub/ance pres5t 9 ei!r phase or 9 bo? phases2 t is1 provid$ ! ratio ( ! conc5trations is ma9ta9$ con/ant at a giv5 temp]ature1 ! quantity ( sub/ance pres5t 9 bo? phases or 9 ei!r phase is v>iable4 ,= in/ance1 ! condition ( equilibrium betwe5 wat] & p#aai wat] vapor is indep5d5t ( ! quantity ( wat] or ( wat] vapor pres5t3 9 a clos$ lit] bottle conta9+ wat] & wat] vapor1 ! ratio ( ! conc5trations is ma9ta9$1 irrespective ( ! "q :e!r ! bottle conta9s #aj c4c4 ( wat] & #iij c4c4 ( vapor or #iij c4c4 ( wat] & #aj c4c4 ( vapor4 ,! law is "o ( exp]i5ce2 in/ances ( its application are giv5 bel[4 ,its probable !oretical significance may be expla9$ me*anically ) ! aid ( ! k9etic !ory ( gases & solutions1 z foll[s3 ,if *lor(orm is add$ to a solution ( brom9e 9 wat]1 ! *lor(orm takes up "p ( ! brom9e &1 if ! mixture is vigor\sly %ak51 a condition ( equilibrium & a def9ite di/ribution ( brom9e betwe5 ! two solv5ts w result 7exp4#bbh74 ,n[1 if "o imag9es a lit] ( ! aque\s solution to conta9 "o mole ( brom9e at "s giv5 temp]ature & to cov] a lit] ( *lor(orm1 ! :ole sy/em be+ left to itself1 !n all ! conditions affect+ ! migration ( ! brom9e into ! *lor(orm w be def9ite ones--! conc5tration ( ! brom9e1 ! temp]ature1 ! surface betwe5 ! two solv5ts--& brom9e w pass f ! aque\s solution into ! *lor(orm solution at a def9ite spe$4 ,we may call ! quantity 79 moles7 ( brom9e :i* w\ld ent] ! *lor(orm 9 "o m9ute1 if ! conc5tration ( ! brom9e 9 ! wat] 7 kept con/ant 7"o mole7 ?r\gh\t ! m9ute1 ! velocity ( migration ( ! brom9e--?is velocity1 l *emical velocity1 repres5t+ a quantity1 n a di/ance4 ,! velocity be+ a def9ite "o "u ^! conditions1 we h v#a k#a4 ,n[1 if all ! conditions are left unalt]$1 except t ! conc5tration ( ! brom9e is *ang$1 say kept at "o-hundr$? its orig9al value1 !n only "o "o-hundr$? z _m molecules ( brom9e z 9 ! fir/ case w come into contact ) ! *lor(orm surface 9 unit "t4 ,! *ances = migration are "o "o-hundr$? z great1 & ! quantity ent]+ ! *lor(orm 9 unit "t--! velocity ( ! p#abj *ange--w be "o "o-hundr$? ( ! orig9al velocity4 ,9 g5]al1 ! velocity w be proportional to ! conc5tration ( ! brom9e ,braq4 9 ! wat] at any mom5t & to ! *>act]i/ic con/ant k#a4 v#a ,braq4 k#a4 ,on ! o!r h&1 if a solution ( brom9e 9 *lor(orm is cov]$ ) wat]1 brom9e ent]s ! wat] 7exp474#bbi ,we w\ld f9d1 by ! me?od ( analysis us$ be=e1 & = ! same conditions1 t ! velocity ( migration1 v#b1 ( ! brom9e into ! wat] is also proportional to a *>act]i/ic con/ant1 k#b1 & to ! conc5tration ( ! brom9e 9 ! *lor(orm ,br*44 ,we h1 !re=e v#b ,br*4 k#b4 ,equilibrium betwe5 ! two solutions w be rea*$ :5 v#a v#b or ,braq4 k#a ,br*4 k#b1 f :i* foll[s t#bcj = ! condition ( equilibrium ,braq4 _/ ,br*4 k#b _/ k#a k4 ,applications ( ! ,law ( ,physical ,equilibrium4--7#a7 ,! law ( physical equilibrium may be appli$ fir/ to ! case ( a liquid1 say *lor(orm1 9 contact ) its vapor4 ,= ! condition ( equilibrium at a fix$ temp]ature ,c,h,cl#cvap4 3 ,c,h,cl#cliq4 k4 ,n[1 at a fix$ temp]ature1 a pure liquid has a fix$ conc5tration1 its specific gravity be+ a def9ite "o4 ,h5ce1 = a fix$ temp]ature1 ! second t]m ( ! con/ant ratio be+ def9ite1 ! fir/ t]m1 ,c,h,cl#cvap41 repres5t+ ! conc5tration ( ! vapor1 mu/ also h a fix$1 con/ant value = ! condition ( equilibrium1 i4e4 :5 ! space above ! liquid is saturat$ ) its vapor4 ,?is is 9 agreem5t ) well-kn[n facts4 ,! conc5tration ( ! vapor is usually express$ 9 t]ms ( its p#aba pressure1 & is call$ ! vapor pressure or vapor t5sion ( ! liquid at ! temp]ature 9 "q4 ,tables giv+ ! def9ite vapor pressures ( important liquids at ! v>i\s fix$ temp]atures are 9 common use4 7#b7 ,= oxyg5 9 equilibrium ) its saturat$ solution1 say 9 wat]1 at a fix$ temp]ature1 we h1 accord+ to ! law1 ,o#b;gas 3 ,o#bsolut4 k4 ,if ! oxyg5 is "u a giv5 pressure at a def9ite temp]ature1 its conc5tration ,o#b;gas is fix$1 & consequ5tly ! second t]m1 ,o#bsolut41 ( ! ratio1 ! conc5tration ( ! dissolv$ oxyg51 or its solubility1 mu/ also be def9ite1 i4e4 oxyg5 mu/ h a def9ite solubility 9 wat] at a giv5 temp]ature "u a giv5 pressure4 ,if ! pressure on ! gas is d\bl$1 its conc5tration is d\bl$ &1 to ma9ta9 ! con/ant ratio1 its solubility mu/ also be d\bl$--:i* is 9 agreem5t ) ! facts 7,h5ry's law74 ,if air ( ! same pressure is tak51 9 place ( pure oxyg51 !n ! conc5tration ( ! oxyg5 7fir/ t]m ( ! above ratio7 is only ab\t "o-fif? z great z = ! pure gas1 & ! wat] mu/ be saturat$ ) oxyg5 :5 x has tak5 up only "o-fif? 7second t]m ( ! ratio7 z mu* z x w\ld f ! pure gas 7,dalton's law73 ,ea* gas 9 a mixture is soluble 9 proportion to its own p>tial pressure or conc5tration4 7#c7 ,= sug> 9 equilibrium ) its solution 9 wat]1 i4e4 9 contact ) its saturat$ solution1 at a giv5 temp]ature1 we %\ld h ,c#ab;,h#bb,o#aa;aq4 3 ,c#ab;,h#bb,o#aasolid k4 ,s9ce a pure solid l sug> at a giv5 temp]ature has a def9ite specific gravity1 ! conc5tration ( ! sug> 9 ! solid condition %\ld also be a def9ite "o4 ,consequ5tly1 accord+ to ! law "u discussion1 ! fir/ t]m1 ,c#ab;,h#bb,o#aa;aq41 ( ! ratio1 ! conc5tration ( ! sug> 9 its saturat$ solution 9 contact ) ! solid phase1 mu/ also h a def9ite value4 ,?is is 9 agreem5t ) fact1 ! conc5tration ( ! sug> 9 ! saturat$ solution1 t]m$ its solubility1 be+ a def9ite "o = a giv5 temp]ature4 7,see bel[1 p4 #abc1 9 reg>d to ! solubility ( f9e p[d]s47 ,sup]saturat$ ,solutions4-- ,x is well kn[n1 h[ev]1 t by dissolv+ a sub/ance1 su* z sug>1 9 hot wat] & c>efully p#abb cool+ ! solution1 we may obta9 a solution ( sug> conta9+ mu* m sug> 9 unit volume ?an is repres5t$ by its solubility at ! l[] temp]ature4 ,! conc5tration ( ! sug> at ! temp]ature 9 "q1 in/ead ( hav+ ! def9ite value repres5t$ by ,c#ab;,h#bb,o#aa;aq41 c easily h a value sev]al times z l>ge4 ,?is ph5om5on is n at v>iance ) ! law ( physical equilibrium1 inasmu* z ! law /ates t1 :5 a giv5 comp\nd is pres5t 9 two physical /ates or phases1 !n a con/ant ratio betwe5 ! conc5trations ( ! sub/ance 9 ! two phases is e/abli%$ :5 equilibrium is rea*$ at a giv5 temp]ature4 ,9 ! solution prep>$ z describ$1 we h ! sub/ance pres5t only 9 "o phase1 & we h :at may be call$ a meta/able condition1 z long z ! second phase is n introduc$4 ,z soon z a m9ute cry/al ( ! solid phase is add$ or is =m$ 9 ! solution1 *ange imm$iately ensues1 & ! excess ( solid is deposit$4 ,if ! mixture be kept p]fectly quiet1 ! excess w 9 mo/ cases be deposit$ on ! surfaces ( ! add$ cry/al1 :i* !reby gr[s l>g] 7rock-c&y manufacture74 ,,exp4 ,sup]saturat$ solutions ( sodium sulphate & sodium ?iosulphate1 into :i* cry/als ( ! salts are dropp$1 %[ h[ ! cry/al />ts cry/allization4 ,! cry/als develop z bran*es f ! cry/al fir/ introduc$ & f ! new cry/als =m$4 ,?is ph5om5on ( sup]saturation is "o :i* analytical *emi/s mu/ always take into consid]ation4 ,te/s :i* involve ! precipitation ( sub/ances t are m]ely difficultly soluble1 r ?an exce$+ly insoluble1 or ( sub/ances pres5t only 9 v small quantities1 may well lead to entirely wrong conclusions1 if precautions are n tak5 aga9/ ! possibility ( ! failure ( a precipitate to appe> z a consequ5ce ( p]si/5t sup]saturation4 ,= in/ance1 a common te/ = ! pres5ce ( potassium salts consi/s 9 ! precipitation ( potassium acid t>trate by ! addition ( t>t>ic acid to ! solution ( a potassium salt 7exp474 ,! t>trate is some:at soluble & t5ds to =m sup]saturat$ solutions2 if we proce$ )\t due reg>d = ?is ph5om5on1 we may readily h a quantity ( potassium salt pres5t & fail to obta9 ! te/ = x4 ,simply mix+ t>t>ic acid & potassium *loride solutions 7exp47 may fail to p#abc give any precipitate1 & if ! te/ is ?r[n away & potassium report$ abs5t1 a gl>+ blund] is committ$4 ,to insure aga9/ ! error ( sup]saturation1 we try to />t cry/allization by ! common devices ( %ak+ ! solution or scrat*+ ! walls ( ! vessel1 ! object be+ to facilitate ! =mation ( ! fir/ cry/al4 ,! sure/ me?od is to inoculate a small portion ( ! mixture ) a m9ute cry/al ( ! sub/ance we expect to be =m$4 ,if no precipitate results 9 a %ort "t1 ! solution is n sup]saturat$--x may be too dilute & may require fur!r conc5tration1 b ! error ( sup]saturation has be5 exclud$4 ,! relation betwe5 sup]saturat$ solutions & cry/als br+s out %>ply ! fact t physical equilibrium is ess5tially a condition ( equilibrium betwe5 ! sub/ance at ! surface ( ! solid & ! sub/ance 9 its dissolv$ /ate4 ,9 t]ms ( ! molecul> !ory1 equilibrium is e/abli%$ :5 ! molecules ( ! cry/al surface dissolve z rapidly z molecules f ! solution are deposit$ on ! surface4 ,if ! conc5tration ( ! dissolv$ molecules is r$uc$ bel[ ! po9t requir$ = equilibrium1 ! velocity ( deposition is dim9i%$4 ,! velocity ( solution w !n be great] ?an ! velocity ( deposition & solution w result4 ,! rev]s$ relations hold :5 ! conc5tration ( ! solution is great] ?an t dem&$ by equilibrium3 ! velocity ( deposition w be ! great] ?an t ( solution & precipitation foll[s4#bca ,solubility ( ,f9e ,p[d]s4--,consid]ation ( ! surface =ces1 act+ betwe5 cry/als & ! liquids wett+ !m1 l$ to ! int]e/+ pr$iction#bcb t ! m m9ute cry/als ( a giv5 specim5 w\ld n only dissolve m rapidly1 on acc\nt ( ! l>g] surface expos$1 b w\ld also be m soluble ?an ! l>g] cry/als1 & = ! same reason4 ,surface t5sion always t5ds to produce ! smalle/ possible free surface ( a liquid1 & ! free surface betwe5 a liquid & a giv5 weight ( solid mat]ial 9 a f9e p[d] is mu* l>g] ?an betwe5 ! liquid & ! same weight 9 l>g] cry/als4 ,! surface t5sion p#abd w !re=e t5d to conv]t ! small] cry/als into l>g] ones1 & x c d s only by means ( a great] degree ( solubility ( ! =m]4 ,?is pr$iction has n[ be5 fully v]ifi$ by exp]im5ts on ! solubility ( b>ium sulphate & ( gypsum4#bcc ,! solubility ( b>ium sulphate 9 a v f9e p[d] 7) an av]age diamet] ( #ajd mm47 is almo/ twice z great z ! solubility ( a co>s] mat]ial 7#ah;,e#d mm4 av]age diamet]74 ,! application ( ^! relations to analysis is z foll[s3 ,if a cry/all9e precipitate is 9 contact ) a solv5t1 e4g4 if b>ium sulphate is 9 contact ) ! liquid f :i* x has be5 precipitat$1 !n ?is liquid mu/ be cont9ually 9 a /ate ( *ange1 n ( equilibrium1 ) respect to ! solution & ! deposit$ b>ium sulphate4 ,! m m9ute cry/als1 be+ a little m soluble ?an ! l>g] ones1 w sup]saturate ! solution 9 respect to ! l>g] cry/als & ! excess w be deposit$ on ^! l>g] cry/als & make !m gr[ /ill l>g]4 ,?is deposition w make ! solution unsaturat$ ) respect to ! small] cry/als & m ( ^! w dissolve4 ,! process is obvi\sly a cont9u\s "o1 & mu/ lead 9 "t to ! disappe>ance ( ! m9ute cry/als & ! gr[? ( ! l>g] ones4 ,t is a result :i* analy/s aim to atta91--:i* 9 quantitative "w x is 9 fact necess>y to atta91 s9ce ! m m9ute cry/als are likely to pass ?r\gh filt]s & be lo/ 9 ! analysis4 ,! views express$1 & ! exp]im5tal confirmation ( ! conclusion rea*$1 =m ! !ory ( :at is call$ ! dige/+ ( precipitates be=e !y are br\ght on filt]s4 ,x is cle> t e condition facilitat+ contact betwe5 solv5t & solid w accel]ate ! desir$ *ange & cont9u\s /irr+ is !re=e desirable4 ,heat+ is1 z a rule1 also to be desir$ = v insoluble precipitates1 z x w1 9 ! majority ( cases1 facilitate ! solution ( ! undesirable1 f9] cry/als4 ,9 conclusion1 ^! consid]ations w also indicate ! precautions to be obs]v$ 9 ! precipitation ( difficultly soluble sub/ances4 ,if ?is is n prop]ly c>ri$ out1 endless tr\ble 9 p#abe ! analytical laboratory results4 ,except :5 heat+ is1 = "s special reason1 undesirable--z induc+ a *emical *ange 7l hydrolysis7 t is n want$--solutions are br\ght to ! boil+-po9t1 & ! precipitant add$ drop by drop1 9 ord] n to sup]saturate ! solution too /rongly4 ,! solution is ?us all[$ "t to deposit its excess z f> z possible on ! fir/ cry/als =m$1 :i* x w d r ?an to =m new1 m9ute ones 7see sup]saturation1 p4 #aba74 ,con/ant /irr+ is prescrib$ 9 ord] to br+ old] cry/als1 z f> z possible1 into contact ) all p>ts ( ! slightly sup]saturat$ solution4 ,aft] ! precipitation is complete1 x is usually desirable to all[ ! mixture to dige/ = "s "t1 = ! reasons giv5 above--/irr+ & a high temp]ature dur+ ! process be+ desirable4 7,see fur!r ,*ap4 ,,viii1 p4 #adg1 9 reg>d to ! use ( an excess ( precipitant47 ,,! ,,colloidal ,,condition ,:5 a difficultly soluble sub/ance is =m$ 9 a solution beyond ! po9t ( saturation ( ! solution1 ! sub/ance 9 "q sep>ates f ! solution 9 a new phase1 accord+ to ! pr9ciples j laid d[n4 ,ord9>ily1 if ! sub/ance is a solid1 a precipitate is =m$2 if a gas1 a gas escapes2 if a liquid1 a liquid sep>ates out1 :i* is immiscible ) ! solution 9 :i* x is =m$4 ,occasionally1 ! condition ( sup]saturation :i* prec$es ! sep>ation is some:at p]si/5t1 b ?is resi/ance to ! sep>ation ( ! phase may be ov]come by vigor\s agitation ( ! solution or1 z 9 ! case ( sup]saturation ) a cry/allizable salt1 by inoculation ( ! solution ) a p>ticle ( ! new phase 7p4 #abc74 ,"u c]ta9 conditions1 h[ev]1 a difficultly soluble sub/ance may be produc$ 9 a solution1 9 a conc5tration f> beyond its solubility1 )\t ! sep>ation ( a precipitate 7evolution ( a gas or =mation ( a sep>ate liquid7 & also )\t ! =mation ( a sup]saturat$ solution4 ,?us1 :5 hydrog5 sulphide is pass$ into an aque\s solution ( ars5i\s oxide1 ! liquid acquires ! yell[ to orange color ( ars5i\s sulphide & becomes opalesc5t4 ,b no precipitate is se5 7exp471 9 spite ( ! fact t ! sulphide is extremely insoluble & is =m$ practically quantitatively accord+ to ! equation ,z#b,o#c #c ,h#b,s ,z#b,s#c #c ,h#b,o4 ,! orange liquid passes ?r\gh a p#abf filt] un*ang$ 7exp474 ,b if "s hydro*loric acid or a salt 7e4g4 sodium *loride7 solution is add$ to a portion ( x1 a heavy precipitate ( ars5i\s sulphide is imm$iately produc$ 7exp472 its quantity is a good indication ( ! great am\nt ( sulphide t is n precipitat$ be=e ! addition ( ! acid or salt4 ,if "s pure ars5ic sulphide 7solid7 is add$ to ano!r portion ( ! orange liquid1 9 ord] to ov]come any possible condition ( sup]saturation1 ! liquid is f\nd to rema9 cle> 7b opalesc5t71 except+ = ! few p>ticles ( add$ sulphide 7exp472 ev5 :5 x is vigor\sly %ak5 7exp471 or all[$ to /& = days1 no precipitate is =m$4 ,we are !re=e n deal+ ) a case ( sup]saturation4 ,a liquid1 9 :i* a v insoluble sub/ance appe>s ?us to be 9 solution f> beyond its usual degree ( solubility1 & yet does n %[ at all ! behavior ( a sup]saturat$ solution1 is said to conta9 ! sub/ance 9 ! colloidal condition4 ,aft] a few m in/ances ( ! colloidal condition h be5 pres5t$1 ! significance ( ! condition & ! mean+ ( ! t]m us$ to designate x w be expla9$4 ,colloidal ,gold4--,:5 a solution ( gold *loride#bcd is treat$ ) a solution ( /ann\s *loride :i* conta9s a little /annic *loride1#bce a purple-r$1 floccul5t precipitate--! purple ( ,cassius--is =m$2 9 extremely dilute solutions only a purple-r$ liquid#bcf may be produc$4 ,if ! precipitate is collect$ on a filt]1 wa%$ ) wat] & !n treat$1 on ! filt]1 ) a few drops ( ammonium hydroxide solution & "s wat] 7exp471 x is se5 to dissolve & a beautifully color$ liquid1 ( purple-r$ or cl>et-r$ t9t1 is f\nd to pass ?r\gh ! filt]4 ,9 spite ( ! extreme insolubility ( metallic gold1 ! r$ ammoniacal solution 7z well z ! fir/ r$ precipitate7 conta9s metallic gold1 9 ! colloidal condition1 =m$ accord+ to ! equation#bcg #b ,au#c #c ,sn#b #b ,au #c ,sn#d4 ,by ! c>eful p#abg r$uction ( gold *loride ) phosphorus1#bch or ) =maldehyde 9 dilute1 slightly alkal9e solution1#bci brilliant r$ liquids1 conta9+ metallic gold 9 ! colloidal condition1 may be prep>$1 :i* rema9 cle> = mon?s4 ,! passage ( an electric curr5t1 9 ! =m ( an arc1 betwe5 two gold po9ts "u pure wat] produces simil> r$ liquids#bdj conta9+ metallic gold4 ,colloidal ,silv]4--,fur!r1 al?\gh silv] is likewise an extremely insoluble metal1 solid prep>ations ( silv] are kn[n :i*1 on treatm5t ) wat]1 =m app>5tly p]fectly cle> 7opalesc5t7 liquids or solutions 7exp474#bda ,f ^! silv] is n deposit$1 ev5 9 ! c\rse ( mon?s4 ,if a little ( ! black solid is heat$ on ! lid ( a porcela9 crucible1 ! metal may be readily recogniz$ by its :ite color & lu/]4#bdb ,colloidal ,f]ric ,hydroxide4--,fur!r1 if to a solution ( f]ric *loride an excess ( ammonium hydroxide is add$1 ! well-kn[n1 ru/-r$ precipitate ( v difficultly soluble f]ric hydroxide is =m$3 ,fe,cl#c #c ,,nh#d,,oh ,fe7,,oh7#c #c ,,nh#d;,cl4 ,! precipitate is s insoluble t x is a favorable =m = precipitat+ ! f]ric-ion 9 quantitative analysis4 ,if1 h[ev]1 a solution ( f]ric *loride be c>efully neutraliz$ ) ammonium c>bonate#bdc & be !n plac$ 9 a vessel 7call$ a dialyz]71 9 su* a way t x is sep>at$1 by an animal membrane or by p>*m5t1 f pure wat]1 f]ric hydroxide is obta9$ 9 an app>5tly soluble =m4 ,! ammonium *loride1 z well z hydro*loric acid :i* is =m$ by ! decomposition ( ! *loride by wat] 7,fe,cl#c #c ,,hoh ,fe7,,oh7#c #c ,h,cl1 see ,*apt] ,x71 are f\nd to pass ?r\gh ! membrane readily1 :ile ! f]ric hydroxide produc$ does n pass ?r\gh su* p#abh membranes#bdd & is reta9$ 9 ! dialyz] )\t =m+ a precipitate4 ,! acid & salt pass ?r\gh su* membranes 9 ei!r direction1 inde$1 b fl[ ma9ly f _! solutions ( high] conc5tration to ^? ( l[] conc5tration4 ,! wat] on ! outside ( ! dialyz] is1 !re=e1 cont9u\sly r5ew$1 9 ord] to insure a conc5tration ( ^! sub/ances on ! outside ( ! dialyz] l[] ?an t )9 x4 ,z ! hydro*loric acid is ?us remov$ ?r\gh ! membrane1 ! condition ( equilibrium betwe5 ! f]ric *loride1 wat]1 f]ric hydroxide & acid is cont9u\sly di/urb$ &1 9 ! rev]sible reaction1 express$ 9 ! above equation1 ! action is c>ri$ m & m t[>ds ! "r1 & m & m f]ric hydroxide is =m$4 ,! salt is1 at la/1 practically all decompos$ & a cle> r$ opalesc5t liquid1 :i* conta9s f]ric hydroxide 9 enorm\s excess beyond its solubility 9 wat]1 is left 9 ! dialyz]4 ,exactly z 9 ! case ( ! o!r liquids discuss$ above1 9 :i* v insoluble sub/ances appe> to be 9 solution f> beyond _! usual degree ( solubility1 s ! pres5t liquid does n %[ ! behavior ( a sup]saturat$ solution & x is said to conta9 ! f]ric hydroxide 9 ! colloidal condition4#bde ,solution ,!ory ( ! ,colloidal ,condition4--,= _m ye>s ! belief 0 preval5t among *emi/s t ^! liquids repres5t true solutions ( difficultly soluble sub/ances1 9 ! =m ( soluble 7colloidal7 modifications ( ! sub/ances4 ,l ord9>y p#abi solutions1 ! liquids are f\nd1 inde$1 to %[ a c]ta9 osmotic pressure1 b1 unlike ord9>y solutions1 ! osmotic pressure is exce$+ly small 9 proportion to ! quantity ( ! sub/ance pres5t4 ,s9ce ! osmotic pressure is proportional to ! numb] ( molecules 9 unit volume 7,*ap4 ,,ii71 ?is obs]vation prov$ ! pres5ce ( a relatively v small numb] ( molecules 9 solution1 & *emi/s 7 l$ to assign1 !re=e1 a relatively v great weight to ea*4 ,h5ce1 ! data l$ to ! assumption t ! colloidal modifications consi/ ( molecules ( v l>ge1 sometimes enorm\s molecul> weight4 ,f ! fact t colloids are unable to trav]se membranes1 ?r\gh :i* cry/alloids readily pass1 ,graham _h rea*$ ! same conclusion4 ,! foll[+ measurem5ts ( osmotic pressures may be giv53#bdf ,osmotic ,sub/ance4 ,conc5tration ,pressure4 ,p] c5t4 ,cm4 ,hg4 ,gum arabic #a #f4i ,dextr9 #a #af4f ,z#b,s#c #d #a4g ,fe7,,oh7#c #a4a #j4h #b4j #b4h #c4j #e4f #e4c #ab4e #h4i #bb4f ,! la/ results1 obta9$ ) special c>e to exclude soluble impurities1 are m reliable ?an ! old] results on gum arabic & dextr94 ,= ! purpose ( comp>ison x may be said t a #a solution ( cane sug> 7molecul> weight #cdb7 has an osmotic pressure ( #ec cm4 ,hg at #ah1 a #e solution a pressure ( #bfe cm4 ,! ,susp5sion ,!ory ( ! ,colloidal ,condition4--,on ! o!r h&1 a numb] ( *emi/s consid]$ ! colloidal liquids to repres5t1 ess5tially1 susp5sions ( m9ute solid p>ticles#bdg 9 an extreme /ate ( subdivision1 or1 9 "s in/ances1 p]fect p#acj emulsions ( difficultly miscible liquids4#bdh ,obs]vations ) ! ultramicroscope#bdi f9ally prov$1#bej beyond "q1 ! correctness ( ?is !ory ( ! colloidal condition4 ,?us1 ! colloidal solutions ( gold are se5 to conta9 m9ute solid p>ticles ( gold1 ! diamet] ( :i* v>ies#bea betwe5 7approximately7 #fj & #f & ! color ( :i* v>ies ) _! size4 ,/ill f9] subdivisions1 ! diamet] ( ^: p>ticles _c be measur$1 are also f\nd to exi/4 ,colloidal silv]1 plat9um1 ars5i\s sulphide & o!r colloidal metals & sulphides h also be5 %[n1 9 ! same way1 to be susp5sions ( solid p>ticles4 ,! ,g5]al ,"* & ! ,def9ition ( ! ,colloidal ,condition4--,rec5t inve/igations h %[n t ! colloidal condition is possible1 n only = a limit$ class ( sub/ances1 b is1 9 g5]al1 possible = all sub/ances4#beb ,?us1 ev5 su* an em95tly cry/allizable1 readily soluble 79 wat]7 sub/ance z sodium *loride may be obta9$1 "u c]ta9 conditions1 9 colloidal susp5sion 9 b5z5e1#bec 9 :i* x is insoluble4 ,= our purposes x w be suffici5t to def9e ! colloidal condition1 on ! basis ( ^! results1 z ! condition ( an insoluble sub/ance 9 :i*1 z f> z ord9>y obs]vation & ! common me?ods = sep>ation ( het]og5e\s phases 7filtration1 s$im5tation1 etc47 are conc]n$1 ! sub/ance appe>s to be pres5t 9 a homog5e\s cle> solution1 :]eas 9 reality x is pres5t 9 a het]og5e\s mixture4 ,an extremely f9ely divid$ solid susp5d$ 9 a liquid1 or an emulsifi$ liquid susp5d$ 9 ano!r liquid1 are ! mo/ common types#bed ( su* mixtures4 p#aca ,relations to ,analysis4--,s9ce ! colloidal condition ( insoluble sub/ances int]f]es ) ! precipitation ( ! latt]1 & ) _! sep>ation by filtration f ! liquids 9 :i* !y are susp5d$1 & s9ce ! majority ( ! sep>ations & te/s ( analytical *emi/ry dep5d on ! successful =mation ( precipitates & on _! successful sep>ation by filtration1 analytical *emi/ry is prim>ily#bee conc]n$ ) ! colloidal condition z a condition t is to be avoid$ z completely z possible 9 ord] to escape error4 ,9 o!r fields ( *emi/ry1 notably 9 physiological *emi/ry & 9 "s bran*es ( te*nical *emi/ry1 x is a s\rce ( effects s mom5t\s & specific t a new bran* ( *emi/ry1 ! *emi/ry ( colloids1#bef has gr[n out ( ! inve/igations ( its relations & laws4 ,! pres5t discussion w be limit$ to ! pres5tation ( su* ( ! fundam5tal facts conc]n+ ! colloidal condition z are ( *ief importance 9 analytical "w4#beg ,electrical ,conditions ( ,colloids4--,"o ( ! mo/ important discov]ies made on colloids is ! obs]vation t ! susp5d$ p>ticles ( a l>ge class ( colloids c>ry electrical *>ges1 s t !re is a pot5tial diff]5ce betwe5 ! p>ticles & ! liquid 9 :i* ! susp5sion exi/s4#beh ,?us1 9 ! colloidal susp5sion ( ars5i\s sulphide 7prep>$ z describ$ on p4 #abe7 ! sulphide p>ticles c>ry negative *>ges1 & ! solution ba?+ !m is positive4 ,conv]sely1 colloidal f]ric hydroxide 7p4 #abg71 9 wat]1 is *>g$ ) positive1 ! wat] ) negative1 electricity4 ,! exi/5ce & "* ( ^! *>ges may be readily demon/rat$ by ! passage ( a curr5t ( electricity ?r\gh ! colloidal susp5sion 9 ,u tubes 7exp474#bei ,colloidal ars5i\s sulphide is f\nd to migrate t[>d ! positive pole1 f]ric hydroxide p#acb to ! negative pole1 ! movem5t be+ easily foll[$ by ! color ( ! susp5d$ p>ticles4 ,! foll[+ colloids1 :i* are ( int]e/ 9 analytical *emi/ry1 are f\nd to c>ry a negative *>ge 9 pure wat]3 ,colloidal acids 7silicic1 /annic71 sulphides 7,z#b,s#c1 ,z#b,s#e1 ,cd,s1 etc471 salts 7,ag,i1 ,ag,cl7 & metals 7,au1 ,pt1 ,ag74 ,x is notewor?y t ! susp5sions ( f9ely divid$ clay1 kaol91 qu>tz1 c>bon1 c>ry ! same *>ge z ^! colloidal susp5sions4 ,on ! o!r h&1 metal hydroxides 7f]ric1 alum9ium1 *romic71 & basic sub/ances 9 g5]al1 c>ry positive *>ges4 ,on ! o!r h&1 ! colloids ( "o important gr\p are f\nd to be almo/ )\t any electric *>ges2#bfj ! passage ( an electric curr5t ?r\gh _! susp5sions has little or no effect on !m4 ,p]fectly neutral album5 & gelat9e are common repres5tatives ( ?is gr\p4 ,! *>ge on a colloid seems to be liable to v>iation ) ! nature ( ! liquid 9 :i* x is susp5d$4 ,colloidal plat9um 9 wat] is negative1 9 a mixture ( wat] & alcohol1 positive4#b ,( peculi> int]e/ & importance is ! fact t "s colloids *ange ! "* ( _! *>ge :5 ! liquid1 9 :i* !y are susp5d$1 is made to pass f an acid to an alkal9e condition1 & vice v]sa4#bfa ,= in/ance1 album5#bfb1 colloidal silicic acid#bfc & colloidal /annic acid#bfd are negative 9 alkal9e liquids1 positive 9 acid4 ,! relation ( ^! facts to ! *emical nature ( ! sub/ances w be discuss$ pres5tly4 ,! ,s\rce ( ! ,electrical ,*>ges on ,colloids4--,diff]5t views are held z to ! s\rce ( electrification ( colloidal susp5sions4 ,only ! two views ( mo/ direct int]e/ 9 analysis c be consid]$ "h4 ,9 ! fir/ place1 x is possible t p>tial ionization ( ! colloidal susp5sion produces ! electrical *>ge4 ,x is a significant fact t basic colloids 7metal hydroxides1 "s basic dyes7 receive a positive *>ge1 su* z w\ld be left1 if !y 7 slightly ioniz$ z bases 7or salts ( bases7 & insoluble 7susp5d$7 p#acc positive ions 7 reta9$ by ! p>ticles4 ,t w\ld be ! case1 = in/ance1 if p>ticles ( colloidal f]ric hydroxide1 ,fe7,,oh7#cx1 s5t a few hydroxide ions into solution & ! susp5d$ p>ticles includ$ positive insoluble ions4 ,acid colloids1 on ! o!r h&1 assume a negative *>ge1 z w\ld be expect$ f ?is po9t ( view4 ,!n1 ! behavior ( silicic acid is p>ticul>ly sugge/ive2 9 alkal9e or slightly acid liquids1 9 :i* its ionization z a weak acid is favor$ or pr$om9ant 7,*apt] ,x71 x c>ries a negative *>ge1 ! *>ge t w\ld be left on x1 if x ioniz$1 9 "p1 z an acid or its salt4 ,silicic acid %[s "s slight t5d5cy to ionize also z a base 7see ,*apt] ,x7 & ! basic =m ( ionization w\ld be favor$ by ! pres5ce ( a /rong acid 7,*apt] ,x74 ,colloidal silicic acid1 z /at$ above1 *anges its *>ge f negative to positive z ! solution passes f an alkal9e to a 7/rong7 acid reaction1#bfe j z if1 9 ! acid liquid1 x ioniz$ slightly z a base 7salt ( a base7 & reta9$ a difficultly soluble positive ion4 ,album51 :i* has ! prop]ty ( be+ bo? a base & an acid1#bff %[s ! same *ange ( *>ge#bfg 9 ! colloidal condition & ! *ange has be5 ascrib$#bfh to ! *ange ( basic & acid functions4 ,accord+ to ! o!r ( ! two !ories1 "h consid]$1 ! electrification ( ! colloid may result f :at is kn[n z contact or surface electricity4#bfi ,at ! surface ( two diff]5t sub/ances !re is always a pot5tial diff]5ce4#bgj ,9 ! case ( f9ely divid$ susp5sions1 l ! colloids1 ! contact surfaces are enorm\s1 z comp>$ ) ! surfaces involv$ 9 ord9>y contact4 ,:e!r metals 7,au1 ,pt1 ,ag7 owe _! *>ges to simple contact effects or to _! 7m9imal7 t5d5cy to ionize 7,*apt]s ,,xiv & ,,xv7 is n kn[n4 ,9 fact1 no exact k ( ! s\rce ( electrification ( any colloid has yet be5 obta9$4 ,precipitation ( ,colloids by ,electrolytes & by ,colloids4--,sub/ances 9 ! colloidal condition1 :i* c>ry an electrical *>ge1 are readily precipitat$ by ! addition ( electrolytes to ! colloidal susp5sions 7see ! behavior ( ars5i\s sulphide1 p4 #abf74 ,negatively *>g$ colloids are precipitat$ by ! action ( positive ions1 positively *>g$ colloids by ! action ( negative ions 7,h>dy's rule#bga74 ,! precipitat$ colloid c>ries p#acd ) x a "p ( ! precipitat+ ion#bgb 7adsorption7 & ! weights ( ions1 c>ri$ d[n by a giv5 quantity ( a giv5 colloid1 are proportional to ! equival5t weights ( ! ions4#bgc ,! precipitation ?us appe>s to be intimately associat$ ) ! neutralization ( ! *>ge on ! colloid4 ,9 accordance ) ?is conclusion1 x has also be5 f\nd t a colloid may be precipitat$ by a colloid c>ry+ ! opposite *>ge4#bgd ,?us1 colloidal ars5i\s sulphide1 c>ry+ a negative *>ge1 & colloidal f]ric hydroxide1 c>ry+ a positive *>ge1 mutually precipitate ea* o!r 7exp4#bge74 ,! purple precipitate 7purple ( ,cassius71 :i* is =m$ :5 /ann\s *loride is add$ to gold *loride 7p4 #abf71 conta9s colloidal gold1#bgf :i*1 9 susp5sion1 is *>g$ ) negative electricity1 & colloidal /annic acid1#bgf :i* 9 acid solution1 presumably1 c>ries a positive *>ge#bgg3 ^! two colloids mutually precipitate ea* o!r 9 ! pres5ce ( hydro*loric acid4#bgh ,:5 ! precipitate is treat$ ) an alkal9e liquid 7ammonium hydroxide solution71 ! *>ge on ! /annic acid becomes negative1 bo? colloids acquire ! same *>ge & ! precipitate dissolves1 to =m ! beautifully t9t$ susp5sions ( colloidal gold 7p4 #abf74 ,9 ?is condition ! colloids 7gold & /annic acid7 are s5sitive to precipitat+ electrolytes1 & ! solution is m s5sitive to a mixture ( magnesium nitrate & ammonium nitrate ?an to ammonium nitrate alone 7exp471 z is to be expect$ f a negative susp5sion 7see bel[74 ,! *>act]i/ic diff]5ce 9 behavior betwe5 or?o-1 pyro- & metaphosphoric acids t[>d album51 :i* is us$ z a *>act]i/ic analytical te/ to di/+ui% metaphosphoric acid f ! o!r two acids1#bgi appe>s to be due to simil> relations#bhj3 metaphosphoric acid1 :i* precipitates 7coagulates7 album51 is colloidal1 or?o- & pyrophosphoric acids are n4 ,! p#ace coagulation seems to be ! result ( ! union ( ! negative colloid metaphosphoric acid 7or a complex negative colloidal ion !re(7 ) ! positive colloid album5 7or a positive colloidal ion !re(74 ,! ,precipitat+ ,p[] ( ,electrolytes & ! ,val5ce ( _! ,ions4--,! complete precipitation ( colloids1 :i* c>ry electric *>ges1 dep5ds on ! conc5trations ( ! colloid & ! electrolyte2 9 ?is connection ! important obs]vation has be5 made t ! precipitat+ p[] ( electrolytes increases decid$ly ) ! val5ce ( ! precipitat+ ions 7,h4 ,s*ulze's rule#bha74 ,bival5t ions are f> m effici5t ?an unival5t2 trival5t1 9 turn1 /ill m effective ?an bival5t4 ,?us1 colloidal ,z#b,s#c1 c>ry+ a negative *>ge1 is precipitat$ by ! positive ions ( add$ electrolytes4 ,! addition ( a few drops ( a mol> solution ( ammonium nitrate 7! precipitat+ ion is ,,nh#d7 to #bj c4c4 ( ! colloidal susp5sion#bhb produces a slight precipitate2 complete precipitation requires #c4e to #c4f c4c4 ( ! ammonium nitrate solution4#bhc ,only #j4jf c4c4 ( an equival5t solution#bhd ( magnesium nitrate 7! precipitat+ ion is ,mg#b7 is requir$1 & z little z #j4jae c4c4 ( an equival5t solution ( alum9ium nitrate#bhe 7! precipitat+ ion is ,al#c7 has ! same effect 7exp474 ,an increase 9 val5ce ( ! negative ion1 :i* is n ! precipitat+ ion 9 ?is case1 does n affect ! result appreciably3 #c4e c4c4 ( a solution#bhf ( ammonium sulphate1 7,,nh#d7b,,s#d1 equival5t to ! solution ( ,,nh#d,,no#c1 is also requir$ = ! complete precipitation ( ! colloidal ,z#b,s#c 7exp471 al?\gh ! "o conta9s ! unival5t ion1 ,,no#c1 ! o!r ! bival5t ion1 ,,s#db4 ,conv]sely1 a positively *>g$ colloid1 l f]ric hydroxide1 may be precipitat$ by mu* small] quantities#bhg ( bival5t negative ions ?an ( unival5t ions1 etc4 p#acf ,nonprecipitation ( ,nonelectrifi$ ,colloids by ,electrolytes4--,colloids :i* d n c>ry any electric *>ges ( mom5t 7see p4 #acb7 are also n precipitat$ by dilute solutions ( electrolytes4 ,heat1 ! addition ( conc5trat$ salt solutions 9 great excess 7^: effect is probably a dehydrat+ "o71 or ( o!r solv5ts 7e4g4 alcohol71 are ! ag5ts mo/ commonly us$ to effect coagulation 9 su* cases4 ,protective ,action ( ,colloids on ,o!r ,colloids4--,colloids1 p>ticul>ly su* z are n s5sitive to precipitation by electrolytes1 increase 9 a rem>kable degree ! /ability ( ! colloidal condition ( sub/ances1 t c>ry electrical *>ges &1 ord9>ily1 w\ld be v s5sitive to precipitation4 ,?us1 small quantities ( album5 are us$ to r5d] colloidal silv] prep>ations m /able4 ,tannic acid1 gelat9e & album5 & relat$ comp\nds are frequ5tly us$ z su* protective ag5ts4 ,x is suppos$ t !y =m protect+ films ar\nd ! colloidal p>ticles4 ,applications 9 ,analysis4--,f ! prec$+ discussion we may n[ draw ! foll[+ conclusions conc]n+ ! consid]ation t is to be giv5 to ! colloidal condition z a factor 9 qualitative analysis4 ,! abs5ce ( electrolytes 9 solution mu/ favor ! production ( ! colloidal condition1 :i* w\ld result 9 ! nonprecipitation or solution & consequ5t loss ( sub/ances1 :i* x is int5d$ to precipitate4 ,su* abs5ce ( electrolytes 9 solution is mo/ likely to be met )1 9 ! fir/ place1 9 ! wa%+ out ( precipitates4 ,:5 ! l>g] "p ( ! "m liquor is wa%$ away by ! use ( pure wat]1 _m precipitates %[ a t5d5cy to run ?r\gh a filt]1 =m+ colloidal susp5sions 9 ! pure wat] 9 ! filt] & be+ aga9 precipitat$ z ! colloid mixes ) ! electrolytes 9 ! filtrate4 ,precipitates1 %[+ ?is t5d5cy to assume ! colloidal condition1 are !re=e wa%$ ) appropriate solutions ( electrolytes1 r ?an ) pure wat]4 ,ammonium nitrate solution is mo/ frequ5tly available 9 qualitative analysis1 because nei!r ! ammonium-ion nor ! nitrate-ion t5ds to int]f]e ) ! subsequ5t exam9ation ( ! solution4 ,:5 *loride-ion is n likely to int]f]e1 ammonium *loride may be us$4 ,?us1 ! sulphides ( ! ars5ic1 copp] & z9c gr\ps are wa%$ ) solutions conta9+ ammonium nitrate 7! p#acg *loride may be us$ = ! z9c gr\p#bhh7 r ?an ) pure wat] 7or pure hydrog5 sulphide wat]#bhh74 ,9 quantitative analysis1 alum9ium hydroxide is also wa%$ ) ammonium nitrate solution1 silv] *loride ) acidulat$ 7nitric acid7 wat]1 lead sulphate ) dilute sulphuric acid1 etc4 ,9 ! second place1 if precipitations are attempt$ ei!r 9 r dilute solutions or 9 solutions ( little ioniz$ sub/ances 7ars5i\s acid & hydrog5 sulphide71 ! addition ( an electrolyte is frequ5tly requir$ to insure precipitation4 ,?us1 ! pres5ce ( ammonium *loride1 or nitrate1 9 excess1 is helpful 9 ! precipitation ( ! sulphides ( ! z9c gr\p2 ! addition ( hydro*loric acid 7or o!r electrolyte7 is requir$ to effect ! precipitation ( ars5i\s sulphide f a solution ( ! oxide 7p4 #abf74 ,9 ! next place1 acc\nt mu/ be tak51 9 analytical "w1 ( ! fact t colloids c>ry d[n ) !m ! precipitat+ ion by :i* !y are coagulat$1 a fact :i* may lead to ! loss ( ions :i*1 x is int5d$1 %\ld be kept 9 solution4 ,to a c]ta9 ext5t1 ?is loss may also be avoid$ by insur+ ! pres5ce ( electrolytes 7acids1 ammonium salts7 9 suffici5t conc5tration to cause ! coagulation )\t ! aid ( ! ions :i*1 x is int5d$1 %\ld n be precipitat$4 ,9 view ( ! mu* weak] precipitat+ p[] ( unival5t ions 7( hydro*loric acid1 ammonium nitrate & *loride71 z comp>$ ) t ( polyval5t ions1 :i* may be pres5t1 ! acid & ammonium salts mu/ n be us$ 9 too small conc5trations4 ,9 quantitative analysis1 :5 conditions p]mit x1 ammonium or sodium sulphate is frequ5tly sub/itut$ = ! ammonium salts ( ! unival5t monobasic acids4 ,! wa%+ ( ! precipitat$ colloid ) su* salt solutions gradually removes#bhi ! ions :i* are precipitat$ ) ! colloid & =ms a fur!r safegu>d aga9/ _! loss4 ,b ?is s\rce ( loss is avoid$ only ) great difficulty & is seldom absolutely remov$4 ,f9ally1 ! pres5ce ( protective colloids1 especially ( ! p#ach gelat9e & album5 type1 may int]f]e s decid$ly ) ! common precipitation te/s = ions1 t _! de/ruction is imp]ative1 be=e ^! te/s c be appli$ ) any degree ( confid5ce4 ,?us1 ! mix+ ( solutions 7#j4a mol>7 ( silv] nitrate & hydro*loric acid1 ea* conta9+ "o p] c5t ( gelat9e1 fails to produce ! ord9>y1 *>act]i/ic precipitate#bij ( silv] *loride1 ! reaction :i* is us$ to det]m9e ! pres5ce ( ! silv]-ion 9 sy/ematic analysis4 ,! mixture is opalesc5t &1 9 reflect$ light1 looks opaque-:ite2 on some:at prolong$ /&+ a :ite milk is produc$1 b no precipitate4 ,:5 ! mixture is boil$1 ! same deep :ite milk is =m$1 b no coagulat$ precipitate1 ! mixture runn+ un*ang$ ?r\gh a filt]4 ,hydrog5 sulphide conv]ts ! mixture into a simil> susp5sion ( ! black sulphide4 ,,footnotes3 #bbg ,! ratio is affect$ some:at by ! f95ess ( division ( liquids & solids z a result ( surface t5sion ph5om5a1 z expla9$ bel[4 #bbh ,an aque\s solution ( iod9e & potassium iodide %ak5 ) *lor(orm gives simil> results1 & ! diff]5ce 9 color betwe5 ! two lay]s is an advantage = a lecture exp]im5t4 ,b ! iod9e is p>tially comb9$ ) ! iodide1 accord+ to ,,ki ,i#b ,,ki#c1 or ,i ,i#b ,i#c1 & ! !oretical relations are n s simple z = brom9e 9 aque\s & *lor(orm solutions4 #bbi ,to accel]ate ! action1 ! mixture is %ak5 vigor\sly4 ,aft] ! sep>ation ( ! lay]s1 ! brom9e may be recogniz$ 9 ! aque\s lay] by its color1 or by ! addition ( potassium iodide 7lib]ation ( iod9e74 #bcj ,braq4 & ,br*4 are us$ to express ! actual conc5trations at any giv5 mom5t we wi% to consid]1 = in/ance at ! mom5t equilibrium is rea*$4 ,! ratio k#b _/ k#a = any sub/ance ,s is f\nd to be equal to ! ratio ( ! solubilities ( ! sub/ance 9 ! two solv5ts4 ,t x mu/ be s c be prov$ by apply+ ! law ( physical equilibrium to ! mix$ solv5ts 9 contact ) an excess ( ! sub/ance1 i4e4 to its saturat$ solutions 7see bel[74 #bca ,simil> relations hold = ! condition ( equilibrium betwe5 a liquid & its vapor4 #bcb ,curie1 ,bull4 ,soc4 ,m941 #h1 #ade 7#ahhe72 ,o/wald1 ,grundlag5 d] ,anal4 ,*em41 p4 #bb 7#ahid74 #bcc ,hulett1 ,z4 ,phys4 ,*em41 #cg1 #chd 7#aija74 ,see also ,o/wald1 ibid41 #cd1 #die 7#aijj71 on ! solubilities ( f9ely divid$ m]curic oxide 7yell[ oxide7 & ( l>g] cry/als 7r$ oxide74 #bcd ,a #a _/ #ajjj solution ( ,au,cl#c1 #b aq41 & a #a4b _/ #ajjj solution ( ,sn,cl#b1 #b aq41 may be us$ conv5i5tly4 ,:5 equal volumes ( ! solutions are mix$1 ! desir$ precipitate is =m$4 #bce ,/ann\s *loride is usually suffici5tly contam9at$ ) /annic salt4 ,add a few drops ( brom9e- or *lor9e-wat] to #ajj c4c4 ( a pure /ann\s *loride solution4 #bcf ,! action is an exce$+ly s5sitive qualitative te/ = gold4 ,by a modification ( ! te/ ,donau 0 able to detect z little z #b;,e#i gram ( gold 7,monat%efte f4 ,*em41 #be1 #ede 7#aijd774 #bcg ,! nature ( ! r$uction reaction is discuss$ 9 ,*apt]s ,,xiv & ,,xv4 #bch ,f>aday1 ,proc4 ,royal ,soc41 #h1 #cef 7#aheg71 ,phil4 ,mag4 7#d71 #ac1 #dja 7#aheg7 7,/ud474 #bci ,zsigmondy1 ,liebig's ,annal51 #cja1 #cj 7#ahih74 #bdj ,br$ig1 ,z4 f4 ,elektro*em41 #d1 #ead1 #edg 7#ahih71 & ,anorganis*e ,f]m5te1 #aija4 ,colloidal prep>ations ( plat9um1 silv] & _m o!r metals may be prep>$ 9 ! same way4 ,9 e!r1 colloidal prep>ations ( ! alkali metals may be made 7,sv$b]g1 ,b]4 d4 *em4 ,ges41 #ch1 #cfaf 7#aije71 #ci1 #agjh 7#aijf774 #bda ,arg5tum ,cr$ may be conv5i5tly us$4 ,x conta9s1 ) ! metallic silv]1 a small p]c5tage ( album51 :i* is add$ = reasons discuss$ bel[4 ,br[n solutions are =m$ at once4 #bdb ,fir/ a ?9 film ( black c>bon is produc$ r\nd ! metal1 !n ! latt] appe>s 9 ! =m ( a filigree ( silv]4 #bdc ,= details ( ! prep>ation1 see ,a4 ,a4 ,noyes1 ,j4 ,am]4 ,*em4 ,soc41 #bg1 #id 7#aije74 #bdd ,?is process ( sep>ation ( sub/ances1 :i* d n pass ?r\gh membranes1 f su* z d1 is call$ dialysis4 ,x 0 fir/ us$ by ,graham1 ,trans4 ,royal ,soc41 ,london1 #aea1 #ahc-bbd 7#ahfa7 7,/ud474 #bde ,graham made ! fir/ ext5d$ inve/igations 9 ?is field3 ,trans4 ,royal ,soc41 #aea1 #ahc 7#ahfa72 ,j4 ,*em4 ,soc4 7,london71 #ag1 #cah 7#ahfd7 7,/ud474 ,he f\nd t amorph\s1 gelat9\s bodies l f]ric hydroxide1 alum9ium hydroxide1 silicic acid1 gelat9e1 glue1 dextr91 c>amel1 album5 & simil> bodies d n pass ?r\gh membranes & may be obta9$ by dialysis 9 ! colloidal condition4 ,su* sub/ances 7 call$ colloids by ,graham1 ! "n ref]r+ to ! ,lat9 = gelat9e4 ,sub/ances :i* pass ?r\gh membranes readily 7 f\nd by ,graham to resemble 9 behavior su* bodies z are cry/allizable :5 solid2 su* comp\nds 7 classifi$ by him z cry/alloids4 ,t liquids conta9+ sub/ances 9 ! colloidal condition 7e4g4 ars5i\s sulphide1 gold1 silv] & _m o!r sub/ances7 may be prep>$ by me?ods o!r ?an dialysis1 0 f\nd lat] by _m inve/igators &1 9 a few cases1 previ\s to ,graham1 e4g4 by ,f>aday1 loc4 cit4 ,a brief hi/ory ( ! *emi/ry ( colloids is f\nd z an introduction to ,wo4 ,o/wald's ,kolloid*emie1 pp4 #a-fc 7#aiji74 #bdf ,cf4 ,wo4 ,o/wald1 loc4 cit41 p4 #aic4 #bdg ,be=e ,graham's "t1 & = ! few colloidal liquids !n kn[n1 ?is view 0 held by su* m5 z ,j4 ,b4 ,ri*t]1 ,b]zelius & ,f>aday 7loc4 cit47 7cf4 ,wo4 ,o/wald1 loc4 cit41 p4 #ai74 ,! fir/ ext5d$ exp]im5tal inve/igation 9 support ( x 0 made by ,b>us & ,s*neid]1 ,z4 phys4 ,*em41 #h1 #bgh 7#ahia74 ,br$ig 0 also an e>ly & consi/5t *ampion ( ?is view 7vide 8 ,anorganis*e ,f]m5te1 #aija74 #bdh ,cf4 ,wo4 ,o/wald1 loc4 cit41 pp4 #ajb-aad4 ,graham consid]$ colloidal silicic acid a liquid miscible ) wat] 9 all proportions4 ,accord+ to mod]n ideas1 no true miscibility exi/s1 b a susp5sion or emulsion is =m$ 7see ,o/wald1 p4 #bcg74 #bdi ,si$5topf & ,zsigmondy1 ,drude's ,annal51 #aj1 #a 7#aijc74 ,zsigmondy1 ,colloids & ! ,ultramicroscope 7#aiji71 ,*apt] ,v4 #bej ,zsigmondy1 ,z4 fr ,elektro*em41 #h1 #fhd 7#aijb72 ,si$5topf & ,zsigmondy1 loc4 cit4 #bea ,zsigmondy1 loc4 cit41 p4 #afa4 ,a is #a;,e#f mm4 ,! hydrog5 molecule is consid]$ to h a diamet] ( #j4a 7,o4 ,e4 ,mey]71 ! alcohol molecule "o ( #j4e 7,zsigmondy1 loc4 cit41 plate ,,iv1 p4 #aeg74 #beb ,weim>n1 ,*em4 ,z5tralblatt1 #aijg1 ,,ii1 p4 #abic4 #bec ,paal1 ,b]4 d4 *em4 ,ges41 #ci1 #adcf1 #bhei 7#aijf74 #bed ,o!r v>ieties ( het]og5e\s colloidal mixtures are tabulat$ by ,wo4 ,o/wald1 loc4 cit41 p4 #if4 #bee ,! ,cassius' purple te/ = gold is an in/ance :]e ! colloidal condition is us$ 9 analysis = a positive te/4 ,see ,wo4 ,o/wald1 loc4 cit41 p4 #fh1 = o!r1 simil> applications = positive te/s4 #bef ,vide ,wo4 ,o/wald's ,kolloid*emie1 #aiji1 & ! ref]5ces giv5 by ,noyes1 loc4 cit41 p4 #hf4 #beg ,a g5]al discussion ( ! prep>ation & prop]ties ( colloidal mixtures is giv5 by ,a4 ,a4 ,noyes1 ,j4 ,am4 ,*em4 ,soc41 #bg1 #hf-ajd 7#aije7 7,/ud474 #beh ,picton & ,l9d]1 ,j4 ,*em4 ,soc4 7,london71 #fa1 #afj 7#ahib71 #fg1 #fc 7#ahie71 #ga1 #efh 7#ahig71 etc41 & o!rs4 ,wo4 ,o/wald1 loc4 cit41 p4 #bdj1 gives a li/ ( ref]5ces4 #bei ,! arrangem5t ( ! exp]im5t is describ$ by ,noyes1 loc4 cit41 p4 #ih4 #bfj ,cf4 ,wo4 ,o/wald1 loc4 cit41 p4 #ajh4 ,billitz] has f\nd t gelat9e is positive 9 acid solution1 negative 9 alkal9e1 ,z4 phys4 ,*em41 #ea1 #adg 7#aije74 ,! *>ges are1 h[ev]1 relatively small ones4 #bfa ,billitz]1 ,z4 f4 ,elektro*em41 #h1 #fch 7#aijb74 ,?is is probably true ( all amphot]ic colloids 7,*apt] ,x72 x is also true ( _m o!r sub/ances1 :i* are n pron\nc$ly amphot]ic4 7,cf4 ,p]r91 ,comp4 r5d41 #acf1 #achh 7#aijc72 ,billitz]1 ,z4 phys4 ,*em41 #ea1 #aeg 7#aije747 #bfb ,h>dy1 ,j4 ( ,physiology1 #bd1 #bhh 7#ahii72 ,z4 phys4 ,*em41 #cc1 #chg 7#aijj74 #bfc ,billitz]1 loc4 cit41 p4 #aei2 ,mll]'s ,allgeme9e ,*emie d] ,kolloide1 #aijg1 p4 #gi4 #bfd ,see bel[1 p4 #acd4 #bfe ,9 a slightly acid solution colloidal silicic acid is negatively *>g$2 9 a /rong acid solution1 positively--a relation :i* agrees ) its pr$om9antly acid "*4 #bff ,! g5]al class ( sub/ances1 %[+ bo? basic & acid prop]ties1 ( :i* album5 is a d]ivative1 is describ$ 9 a footnote on glycocoll1 ,*apt] ,x1 p4 #ahh4 #bfg ,h>dy1 loc4 cit4 #bfh ,j4 ,loeb1 ,univ]sity ( ,cali=nia ,publications1 ,physiology1 #b1 #adi 7#aijd74 #bfi ,v little is kn[n ab\t ! nature ( contact electricity4 ,x is ev5 d\btful :e!r x is diff]5t1 9 pr9ciple1 f ionization4 #bgj ,w4 ,o/wald1 ,lehrbu* d] ,*em41 #b1 7#a7 #eec 7#aijc74 #bga ,h>dy1 ,proc4 ,royal ,soc41 #ff1 #aaj 7#ahii72 ,z4 phys4 ,*em41 #cc1 #cia 7#aijj74 #bgb ,picton & ,l9d]1 ,j4 ,*em4 ,soc4 7,london71 #fg1 #fc 7#ahie74 #bgc ,:itney & ,ob]1 ,j4 ,am4 ,*em4 ,soc41 #bc1 #heb-hef 7#aija7 7,/ud474 #bgd ,picton & ,l9d]1 loc4 cit4 #ga1 #egb 7#ahig72 ,lott]mos]1 ,anorganis*e ,kolloide1 p4 #gf2 ,biltz1 ,b]4 d4 *em4 ,ges41 #cg1 #ajie 7#aijd74 #bge ,precipitation is complete only :5 ! colloids are us$ 9 ! proportions requir$ to neutralize ea* o!r's *>ges ,billitz]1 ,z4 phys4 ,*em41 #ea1 #adj 7#aije74 ,! proportions to be us$ mu/ be det]m9$ 9 ea* case1 mo/ simply by trial 7,noyes1 loc4 cit41 p4 #aja71 b quantitative me?ods = det]m9+ ! *>ges1 by titration1 are also kn[n 7cf4 ,billitz]1 loc4 cit474 #bgf ,e4 ,a4 ,s*neid]1 ,z4 anorg4 ,*em41 #e1 #hj 7#ahid74 #bgg ,see ! above discussion on silicic acid4 ,/annic acid has a great] t5d5cy to =m a base ?an has silicic acid4 #bgh ,zsigmondy1 ,liebig's ,annal51 #cja1 #cfa 7#ahih74 #bgi ,cf4 ,fres5ius1 p4 #ccd1 or ,smi?'s ,inorganic ,*emi/ry1 p4 #dfh4 #bhj ,mylius1 ,b]4 d4 *em4 ,ges41 #cf1 #gge 7#aijc72 ,biltz1 ibid41 #cg1 #aaaf 7#aijd74 #bha ,j4 fr prakt4 ,*em41 #be1 #dca 7#ahhb74 #bhb ,! susp5sion us$ is prep>$ by saturat+1 ) hydrog5 sulphide1 an aque\s solution ( ars5i\s oxide4 ,! latt] is saturat$ on a /eam ba?1 cool$ to #bj1 filt]$ & dilut$ ) an equal volume ( wat] be=e x is us$4 #bhc ,eight grams ( ,,nh#d,,no#c p] #ajj c4c4 #bhd #j4f c4c4 ( a t5?-normal solution is us$1 conta9+ #a4bh gram ,mg7,,no#c7b1 #f aq41 9 #ajj c4c4 ,precipitation 0 f\nd to be incomplete ) #j4e c4c4 #bhe #j4ae c4c4 ( a t5?-normal solution is us$1 conta9+ #a4b gram ,al7,,no#c7c1 #d aq41 9 #ajj c4c4 ,precipitation 0 f\nd to be incomplete ) #j4a c4c4 ( ! solution4 #bhf #c4c grams 7,,nh#d7b,,s#d 9 #ajj c4c4 #bhg ,freundli* f\nd1 = in/ance1 t ,na,cl1 ,k,cl1 ,ba,cl#b1 9 equival5t conc5trations1 _h practically ! same effect on colloidal f]ric hydroxide1 b only "o-=tie? z mu* ( a sulphate 7! precipitat+ ion is ,,s#db v]sus ,cl7 0 requir$2 ,z4 phys4 ,*em41 #dd1 #abi 7#aijc74 #bhh ,= o!r reasons 7e4g4 to prev5t oxidation ( ! sulphides71 hydrog5 sulphide is also us$ 9 ! solution = wa%+ ! ars5ic gr\p1 & ammonium sulphide 9 t = ! z9c gr\p 7see ,lab4 ,manual1 pp4 #aja & #aaj74 #bhi ,picton & ,l9d]1 loc4 cit41 & ,:itney & ,ob]1 loc4 cit4 #bij ,a4 ,a4 ,noyes describes a simil> exp]im5t ) sodium *loride & silv] nitrate1 loc4 cit4 p#aci ,,*apt] ,,viii ,,simultane\s ,,*emical ,,& ,,physical ,,equilibrium4--,,! ,,solubility- ,,or ,,ion-,,product4 ,x frequ5tly happ5s t we h to deal1 simultane\sly1 ) conditions ( *emical & ( physical equilibrium1 obta9+ 9 ! same sy/em4 ,= in/ance1 a gas l c>bon dioxide1 9 contact ) its saturat$ solution 9 wat]1 is 9 equilibrium ) ! dissolv$ c>bon dioxide1 & ?is1 9 turn1 is 9 equilibrium ) its hydrate1 c>bonic acid4 ,a sub/ance may be di/ribut$ betwe5 two solv5ts & %[ a diff]5t molecul> weight 9 ! two 7see p4 #ah72 x may exi/1 9 ! "o1 prim>ily 9 polym]ic =m1 & only to a slight ext5t 9 ! simple =m1 ! two =ms be+ 9 equilibrium 7*emical equilibrium74 ,9 ! o!r solv5t1 x may exi/ only 9 its simple molecul> =m1 & ?is w be 9 equilibrium ) ! same simple molecul> =m 9 ! fir/ solv5t 7physical equilibrium74 ,9 matt]s deal+ ) ! solubility ( electrolytes 9 wat]1 &1 !re=e1 9 que/ions ( _! precipitation or solution1 su* simultane\s conditions ( *emical & physical equilibrium are con/antly occurr+4 ,s9ce qualitative analysis deals to a v consid]able ext5t ) j su* precipitates ( salts1 acids & bases1 ^! cases are ( p>ticul> importance to u4 ,e>li] ,d]ivation ( ! ,solubility-,product ,pr9ciple4--,a v simple relation 0 d]iv$ by ,n]n/#bia = ! comb9$ conditions ( *emical & ( physical equilibrium1 :]e difficultly soluble electrolytes 7precipitates7 7 conc]n$4 ,we %all develop ! relation fir/ = a simple salt1 su* z silv] acetate4 ,:5 wat] is add$ to solid silv] acetate1 ! salt w dissolve4 ,if an excess ( ! acetate is us$1 equilibrium w result betwe5 ! solid salt & its solution1 :5 ! solution is saturat$ at ! temp]ature us$4 ,z ! salt dissolves1 x is m or less ioniz$1 & 9 ! saturat$ solution we h a p#adj condition ( *emical equilibrium betwe5 ! salt & its ions3 ,,*#c;,c,o,o,ag ,,*#c;,,coo ,ag4 7#a7 ,if ! law ( *emical equilibrium is appli$ to ?is rev]sible action1 we h 7p4 #ih7 ,,*#c;,,coo ,ag _/ ,,*#c;,c,o,o,ag ,k,ionization4 ,i ,! nonioniz$ silv] acetate is pres5t 9 two phases1 9 ! solid phase & also 9 solution3 ,,*#c;,c,o,o,ag ,,*#c;,c,o,o,ag4 7#b7 ,apply+ ! law ( physical equilibrium to ?is sy/em1 we h fur!r 7p4 #aba7 ,,*#c;,c,o,o,ag _/ ,,*#c;,c,o,o,agsolid ,k4 ,,ii ,! conc5tration ( a pure solid1 z we h se51 may be consid]$ a con/ant at a giv5 temp]ature4 ,consequ5tly1 if we consid] ! "q ( ! size ( ! solid p>ticles z a m9or factor & negligible1 we %all conclude1 t1 = saturat$ solutions ( silv] acetate1 ! conc5tration ( ! solid silv] acetate be+ a con/ant1 ! conc5tration ( ! nonioniz$ or molecul> silv] acetate1 ! fir/ t]m ( our con/ant ratio ,,ii1 mu/ also h "s def9ite1 con/ant value at a giv5 temp]ature4 ,we may call ?is conc5tration ! molecul> solubility ( silv] acetate & may put ,,*#c;,c,o,o,ag ,kmol4 sol4 ,,iii = a saturat$ solution ( silv] acetate 9 wat] at ! giv5 temp]ature4 ,n[1 s9ce ! conc5tration ( ! nonioniz$ silv] acetate1 ,,*#c;,c,o,o,ag1 9 ! saturat$ solution also =ms ! second t]m ( equation ,i1 repres5t+ ! condition ( *emical equilibrium betwe5 ! acetate & its ions1 we obta91 by comb9+ ,i & ,,iii1 ,,*#c;,,coo ,ag ,k,ionization ,kmol4 sol4 ,k,solubility-,product4 ,,iv ,fur!r1 if ! assumption is made t ! pres5ce ( =eign electrolytes1 9 n too conc5trat$ solutions1 does n affect ei!r ! molecul> solubility1 ,kmol4 sol41 ( silv] acetate or its t5d5cy to ionize--z express$ 9 ,k,ionization--!n1 ! p#ada relation1 :i* has be5 develop$1 w\ld hold = saturat$ aque\s solutions ( silv] acetate 9 ! pres5ce ( =eign electrolytes1 z well z = a saturat$1 pure1 aque\s solution4 ,a s+le1 simple equation w\ld ?us express ! conditions = simultane\s *emical & physical equilibrium betwe5 a difficultly soluble ionog51 ( ! type ( silv] acetate1 & its saturat$ solutions1 at a giv5 temp]ature1 9 ! pres5ce or ! abs5ce ( =eign electrolytes4 ,! ,solubility- or ,ion-,product ,pr9ciple4--,we may =mulate ?is important conclusion by /at+1 t1 9 saturat$ solutions ( silv] acetate1 ! product ( ! conc5trations ( its ions has a con/ant value at a giv5 temp]ature4 ,analog\s relations may be develop$ = ! saturat$ solutions ( o!r difficultly soluble ionog5s4 ,! con/ant has be5 call$ ! solubility-product con/ant or ! ion-product con/ant ( ! ionog54 ,= salts l lead iodide ,pb,i#b1 silv] *romate ,ag#b;,cr,o#d1 etc41 ea* molecule ( :i* =ms m ?an "o ( a giv5 ion1 ! conc5tration ( su* an ion is rais$1 9 ! solubility-product1 to ! p[] correspond+ to ! numb] ( ions ( ?is k9d =m$ f a s+le molecule ( ! electrolyte4#bib ,?us1 lead iodide ionizes accord+ to ! equation ,pb,i#b ,pb#b #b ,i &1 = a saturat$ solution ( lead iodide#bic at a giv5 temp]ature1 ,pb#b ,i#b ,k4 ,= silv] *romate1 ioniz+ accord+ to ! equation ,ag#b;,cr,o#d #b ,ag ,cr,o#db1 ! =m ( ! solubility-product equation is ,ag#b ,cr,o#db ,k4 ,9 g5]al1 = a saturat$ solution ( a difficultly soluble salt at a giv5 temp]ature ! product ( ! ion conc5trations1 ea* rais$ to ! p[] correspond+ to ! numb] ( t k9d ( ion =m$ f ! ionization ( "o molecule ( ! salt1 is a con/ant4 ,criticism ( ! ,d]ivation ( ! ,pr9ciple4--,n]n/ develop$ ?is important relation 9 #ahhi1 %ortly aft] ! !ory ( ionization 0 =mulat$4 ,s9ce !n1 h[ev]1 ! s\ndness ( ! !oretical developm5t1 on :i* x 0 bas$1 has be5 r5d]$ op5 to "q 9 a way t c\ld h>dly h be5 =ese5 at t e>ly /age 9 ! developm5t ( ! !ory ( ionization4 ,9 ! fir/ place1 x is kn[n n[ t ! ionization ( easily ioniz+ sub/ances 7/rong electrolytes7 does p#adb n con=m to ! law ( *emical equilibrium 7vide p4 #ajh72 z f> z our pres5t k goes1 ! ratio 9 equation ,i is n a con/ant1 b gr[s l>g] ) an increas+ total conc5tration ( good electrolytes4 ,9 ! pres5t case1 ?is total conc5tration may be increas$ by ! introduction ( =eign salts4#bid ,9 ! second place1 ! second fundam5tal pr9ciple us$1 ! pr9ciple ( ! con/ant solubility ( ! dissolv$ molecul> or non-ioniz$ salt1 z express$ 9 equation ,,iii1 0 que/ion$ & disprov$ by ,arrh5ius 9 #ahii4 ,! molecul> solubility dep5ds on ! total conc5tration ( salts 9 ! solution &1 9 g5]al1 decreases ) increas+ conc5tration ( ! total dissolv$ salts4 ,?is result does n invalidate ! law ( physical equilibrium2 x m]ely means t ! pres5ce ( salts1 especially 9 appreciable quantities1 modifies ! nature ( ! solv5t & *anges its dissolv+ p[]1 mu* z we h diff]5t dissolv+ p[] %[n by diff]5t pure solv5ts1 su* z wat] & alcohol4 ,x appe>s1 h[ev]1 t :ile ! s\ndness ( ?is !oretical developm5t ( ! relations express$ by ! solubility-product mu/ be que/ion$1 nev]!less z a matt] ( exp]im5t1 ! product ( ! ion conc5trations ( a difficultly soluble salt is f\nd1 9 dilute solutions1 to be a con/ant1 or suffici5tly close to a con/ant to satisfy all b ! mo/ rigor\s requirem5ts4#bie ,x is1 9 fact1 q evid5t1 t a decreas+ value = ! second t]m ( ! ratio ,i--namely1 = ,,*#c;,c,o,o,ag1 ! molecul> solubility ( ! salt--z ! total conc5tration ( ! electrolytes pres5t increases1 toge!r ) an increas+ value = ! :ole ratio ,i "u ! same conditions1 are n incompatible ) a con/ant value ( ! fir/ t]m ( ! ratio4 ,t is1 ! product ( ! ion conc5trations1 ,,*#c;,,coo ,ag1 may well rema9 con/ant 7equation ,,iv71 or approximately con/ant1 9 dilute salt solutions1 ev5 if equations ,i & ,,iii d n hold = salt solutions4 p#adc ,:e!r 9 ! case ( all difficultly soluble salts1 z ! total salt conc5tration increases1 ! increas+ values ( ! *emical equilibrium ratio 7equation ,i7 w be s nicely balanc$ by ! decreas+ values ( ! molecul> solubility1 t ! fir/ t]m ( ! fir/ ratio 7! solubility-product7 w always be con/ant1 is a "q dem&+ fur!r ext5d$ inve/igation4#bif ,! range ( ! inve/igation mu/ be ext5sive1 because x mu/ include sev]al o!r classes#big ( salts 7e4g4 ,me#b,x1 ,me,y#b1 etc471 = :i* ! fir/ equation has a diff]5t =m2 = in/ance1 = ,me#b,x1 ,me#b ,x#b _/ ,me#b,x ,k4 ,= ! pres5t we mu/ rema9 cont5t ) ! result ( ! pa/ inve/igations & consid] ! pr9ciple ( ! con/ant solubility-product to be ess5tially an empirical "o4 ,x is an extremely conv5i5t cond5sation1 into a v simple ma!matical =m1 ( ! ma9 factors involv$ 9 ! precipitation & solution ( difficultly soluble salts1 acids1 & bases4 ,x %\ld be us$ ) due k ( its "* & limitations4 ,wa%burn#bih d]ives ! pr9ciple ( ! con/ancy ( ! solubility-product1 )\t involv+ 9 8 d]ivation ! relation betwe5 ions & nonioniz$ molecules--a relation :i*1 z 0 /at$ above1 deviates f ! law ( *emical equilibrium4 ,! deviation1 x w be recall$ 7p4 #aji71 is g5]ally suppos$ to be due to ! fact t ! fundam5tal k9etic assumption :i* mu/ be made to d]ive ! law ( *emical equilibrium f ! k9etic !ory1 ! assumption t !re %\ld be none b negligible =ces ( attraction & repulsion betwe5 ! molecules 7( a gas or solute7 :i* are 9 equilibrium1 is n fulfill$ 9 ! case ( solutions ( /rong electrolytes 7p4 #aji74 ,accord+ to ,wa%burn1 if x is assum$ t ! ions ( an electrolyte fulfill ?is fundam5tal condition & t only ! nonioniz$ molecules d n--! latt] caus+ ! deviation f ! law ( *emical equilibrium--!n ! pr9ciple ( ! solubility-product con/ant foll[s4#bii ,he sees an approximate confirmation ( ! assumption made1 9 ! fact t ! pr9ciple is f\nd1 empirically1 to be true1 & t o!r relations1 develop$ on ! basis ( ! same assumption1 agree ) ! obs]vations made4 p#add ,?is !oretical d]ivation ( ! pr9ciple1 l ! d]ivations ( ! law ( *emical equilibrium & ( all our laws ( dilute solutions1 assumes#cjj t ! nature ( ! solv5t1 & consequ5tly ( ! solution-process1 is n *ang$ by add$ sub/ances1 = in/ance by an excess ( ! precipitat+ ionog54 ,!re c be no "q1 h[ev]1 t ! nature ( ! solv5t mu/ *ange1 z a cont9u\s function1 by ! addition ( electrolytes to solutions4 ,! *ang$ solubilities ( in]t gases 9 salt solutions1#cja & a mass ( o!r evid5ce1#cjb lead to ?is conclusion4 ,! addition ( a half mole ( sodium *loride to a lit] ( wat] r$uces ! dissolv+ p[] ( ! liquid t[>ds oxyg5 at #be by #ae1 i4e4 by #cj p] mole ( salt4 ,a weak electrolyte1 su* z acetic acid1 has practically no effect at ?is conc5tration1 & s ! effect mu/ be *iefly due to ! ions ( sodium *loride2 s9ce ! salt1 9 half-mol> solution1 is ioniz$ #gc1 ! r$uction 9 ! dissolv+ p[] w\ld be #cj _/ #j4gc #da p] mole ( fully ioniz$ salt4 ,! pr9ciple ( ! con/ant solubility-product _c be consid]$ z e/abli%$ = solutions m conc5trat$ ?an #j4b to #j4c mol>2 b x is evid5t t1 9 any compreh5sive !oretical =mulation ( ! pr9ciple = ! range 9 :i* x is f\nd empirically to hold1 ! *ange 9 ! nature ( ! solv5t1 :i* 9 "s cases is conspicu\s 9 #j4e mol> solution1 mu/ be tak5 into consid]ation z a factor ev5 9 m dilute solutions 7say #j4je to #j4c mol>74 ,x seems at pres5t1 q possible1 p]haps ev5 probable1 t ! con/ancy1 9 all b ! mo/ dilute solutions1 is ! result ( ! approximate balanc+ ( two 7or m7 oppos+ factors4#cjc ,:5 we leave ! range ( conc5trations m5tion$1 & g to m conc5trat$ solutions1 ^! factors seem to be less well balanc$ & ! validity ( ! pr9ciple ceases4#cjd ,= ! pres5t x w be safe to consid] ! pr9ciple z an empirical "o1 hold+ = solutions ( total salt cont5t up to #j4be or #j4c mol>4#cje ,= q dilute solutions ! effect ( ! electrolyte on ! solv5t w\ld be negligible1 & only to su* solutions w\ld ! !oretical d]ivation br\ght =w>d by ,wa%burn be applicable4 ,influ5ce ( a ,common ,ion4--,= a saturat$ aque\s solution ( silv] acetate at a giv5 temp]ature1 ! product ( p#ade ! ion conc5trations may be consid]$ a con/ant1 ,,*#c;,,coo ,ag ,k,s4,p44 ,9 su* an aque\s solution1 conta9+ no =eign salts1 ! conc5tration ( ! silv]-ion is equal to ! conc5tration ( ! acetate-ion1 s9ce a molecule ( silv] acetate1 :5 x ionizes1 gives "o silv] ion = e acetate ion =m$4 ,! num]ical value ( ! solubility-product may !n be calculat$1 if ! solubility ( ! salt & its degree ( ionization are kn[n4 ,= in/ance1 at #af "o lit] ( wat] dissolves #aj4jg grams ( silv] acetate1 t is1 #aj4jg _/ #afg1 or #j4jfjc gram-molecule 7mole74 ,conductivity measurem5ts %[ t #gj4h ( ! salt is ioniz$ 9 su* a solution1 & consequ5tly ! conc5tration ( ! silv]-ion is #j4gjh #j4jfjc1 or #j4jdbg4 ,! conc5tration ( ! acetate-ion is ! same1 & ! value ( ! solubility-product con/ant1 obta9$ by ins]t+ ^! quantities 9 ! above equation1 is ,k,s4,p4 #j4jdbg #j4jdbg #j4jjahb4 ,n[1 if1 to ! saturat$ solution ( ! silv] acetate1 !re are add$ a few drops ( a conc5trat$ solution ( sodium acetate or "s cry/als ( solid sodium acetate1 ! conc5tration ( ! acetate-ion is !reby increas$ & ! condition ( equilibrium 9 ! solution is di/urb$3 x ,,*#c;,,coo ,ag ,k,s4,p44 ,! conc5tration ( ! acetate-ion hav+ be5 increas$1 ! ion w comb9e m rapidly ?an be=e ) ! silv]-ion1 & ! conc5tration ( ! nonioniz$ salt w be increas$4 ,! solution be+ already saturat$ ) nonioniz$ silv] acetate1 ! excess =m$ mu/ be precipitat$4 ,z a matt] ( fact1 a precipitate ( silv] acetate is readily obta9$ 9 ?is way 7exp474 ,precipitation w cease :5 suffici5t silv] acetate has cry/alliz$ out to make ! product ( ! conc5trations ( ! ions aga9 equal to ! solubility-product con/ant4 ,if1 aft] ! cry/allization is complete & equilibrium has be5 re/abli%$1 ! acetate-ion is x times z conc5trat$ z x 0 9 ! pure aque\s solution1 ! conc5tration ( ! silv]-ion mu/ be r$uc$ to #a _/ x its orig9al value3 x ,,*#c;,,coo ,ag _/ x ,k,s4,p44 ,precipitation4--,we see ?us t precipitation ( a difficultly soluble ionog5 w result :5 ! product ( ! ion conc5trations p#adf is made great] ?an ! value ( ! solubility-product con/ant = t sub/ance4 ,9 ! second place1 x is se5 t ! conc5tration ( an ion ( an insoluble salt1 :i* c be pres5t 9 ! saturat$ solution ( ! salt1 is dep5d5t on ! conc5tration ( ! o!r ion 7or ions7 ( ! salt4 ,?is fact is a v important "o 9 analytical *emi/ry & x is tak5 advantage ( 9 _m ways1 z we %all pres5tly see4 ,x is cle> t a correspond+ result %\ld be obta9$ :51 to ! saturat$ aque\s solution ( silv] acetate1 an excess ( ! silv]-ion is add$--= in/ance by ! addition ( solid silv] nitrate or ( a little ( a conc5trat$ solution ( ?is salt 7exp474 ,"h aga91 ! product ( ! ion conc5trations is great] ?an ! con/ant1 i4e4 ,,*#c;,,coo y ,ag ,k,s4,p41 & precipitation results4 ,silv] acetate !re=e cry/allizes out1 until 7,,*#c;,,coo _/ y7 y ,ag ,k,s4,p44 ,! foll[+ table %[s ! relations :5 sodium acetate is add$ to ! saturat$ solution ( silv] acetate4 ,column #a gives ! conc5tration ( ! sodium acetate 9 ! solution saturat$ ) silv] acetate1 column #b ! p]c5tage ( ! sodium acetate t is ioniz$1 column #c ! total conc5tration ( silv] acetate 9 ! saturat$ solution1 column #d ! p]c5tage ( x :i* is ioniz$1 column #e ! conc5tration ( ! acetate-ion1 column #f ! conc5tration ( ! silv]-ion & column #g ! value ( ! solubility-product4 #a #b #c #d #e #f #g ,na-,acet4 #ajj p4 ,ag-,acet4 #ajj p4 acetate4 ,ag4 ,k,s4,p44 #j 4444 #j4jfjc #gj4h #j4jdbg #j4jdbg #j4jjahb #j4jfa #gh4f #j4jcib #fd4e #j4jgce #j4jbeh #j4jjahe #j4aai #ge4h #j4jbh #ei4g #j4ajfe #j4jafg #j4jjagi #j4bci #gj4h #j4jbjh #eb4c #j4agbg #j4jaji #j4jjahh ,! second table %[s ! relations :5 an excess ( ! silv]-ion is pres5t1 silv] nitrate hav+ be5 add$ to ! saturat$ silv] acetate solution4 ,! columns h ! same significance z 9 ! fir/ table1 except+ t ! fir/ column gives ! conc5tration ( silv] nitrate pres5t & ! second column its degree ( ionization4#cjf ,x is cle> f ^! results t a difficultly soluble salt is r5d]$ less soluble 7see column #c ( ! tables7 by ! pres5ce ( ano!r salt1 :5 ! p#adg latt] has an ion 9 common ) ! =m]4 ,?is conclusion has be5 well e/abli%$#cjg = a consid]able numb] ( salts4#cjh #a #b #c #d #e #f #g ,ag,n,o#b4 #ajj p4 ,ag-,acet4 #ajj p4 acetate4 ,ag4 ,k,s4,p44 #j4 4444 #j4jfjc #gj4h #j4jdbg #j4jdbg #j4jjahb #j4jfa #hb4j #j4jdag #fd4j #j4jbfg #j4jgfg #j4jjbjd #j4aai #gh4d #j4jcda #eh4f #j4jbjj #j4aadb #j4jjbbg #j4bci #gd4j #j4jaie #ea4g #j4jajj #j4ahji #j4jjahb ,applications 9 ,analysis4--,a few in/ances ( ! application ( ?is relation 9 analysis foll[4 ,! det]m9ation ( ! sulphate-ion is bas$ on ! precipitation ( b>ium sulphate f solutions ( sulphates4 ,! solubility ( b>ium sulphate 9 wat] at #ah is #j4jjbc gram1 or #j4jjbc _/ #bcc #a;,e#e mole p] lit]4 ,9 su* an extremely dilute solution1 ! salt may be consid]$ to be completely ioniz$1 & ! value ( ! solubility-product con/ant is f\nd f ,k,s4,p ,ba#b ,,s#db 7#a;,e#e7b1 or #a;,e#aj4 ,n[1 ! am\nt ( sulphate-ion left 9 solution1 :i* w\ld be ab\t "o milligram p] lit] ( ! aque\s solution1 may be r$uc$ by ! use ( a small excess ( ! precipitant1 b>ium *loride4 ,an excess ( z little z #j4b gram or #j4jja mole ( ,ba,cl#b p] lit] w\ld increase ! conc5tration ( ! b>ium-ion ab\t "o hundr$fold1 & b>ium sulphate w\ld be precipitat$1 until ! conc5tration ( ! sulphate-ion _h be5 r$uc$ ab\t "o hundr$fold4 ,! loss ( ! sulphate-ion is ?us r$uc$ to approximately #j4ja milligram p] lit]4 ,9 pass+1 we may ask :at ! approximate loss ( dissolv$ nonioniz$ b>ium sulphate w\ld am\nt to4 ,! value ( ! ratio 7,ba#b ,,s#db7 3 ,ba,s,o#d1 repres5t+ ! ionization ( b>ium sulphate1 is unkn[n = ! extreme dilution repres5t$ p#adh by ! saturat$ solution4 ,if we assume x to be r\ghly ( ! ord] #bjjj 3 #a1cji ! solubility ( nonioniz$ b>ium sulphate at #ah w\ld be r\ghly #j4je milligram p] lit]4 ,z a rule1 !n1 9 ! abs5ce ( complicat+ conditions1#caj an excess ( ! precipitant promotes ! complete precipitation ( an ionog54 ,wa%+ ( ,precipitates4#caa--,:5 b>ium sulphate has be5 br\ght on ! filt] & ! excess ( precipitant is to be wa%$ out1 !n1 z ! excess ( b>ium *loride is remov$1 ! sulphate becomes m soluble aga94 ,x is advisable1 !re=e1 to wa% ! precipitate z effectively z possible ) a v small volume ( wat]--z a rule1 ! wat] is us$ 9 a v f9e /ream or is appli$ drop by drop4 ,su* precautions are /ill m important 9 ! case ( precipitates :i* are some:at m soluble ?an is b>ium sulphate1 & 9 su* cases ! "q mu/ be consid]$1 :e!r z a wa%+ fluid1 "s solution may n be us$1 :i* conta9s an ion 9 common ) ! precipitate1 & :i* has1 !re=e1 accord+ to ! pr9ciple ( ! solubility-product1 a v mu* small] dissolv+ p[] = ! precipitate 9 "q ?an pure wat]4 ,t is a res\rce ( ! analy/ to :i* rec\rse is occasionally tak54 ,lead sulphate1 = in/ance1 is wa%$ ) a v dilute solution ( sulphuric acid1 r ?an ) pure wat]2#cab potassium cobalt9itrite1 ,k#c;,co7,,no#b7f1 :i* is us$ 9 ! sep>ation ( cobalt f nickel1 is wa%$#cac ) a t5 p] c5t solution ( potassium acetate1 conta9+ a little potassium nitrite4 ,ammonium phosphomolybdate1 us$ 9 det]m9ations ( phosphates1 is wa%$ ) a solution ( ammonium nitrate4 p#adi ,! use ( su* solutions = wa%+ precipitates is limit$ by ! necessity1 fir/1 ( avoid+ salts :i* int]f]e ) subsequ5t op]ations 7e4g4 :i* w\ld leave nonvolatile residues 9 ! subsequ5t ignition ( a precipitate1 t is to be weigh$ aft] ignition7 &1 second1 ( avoid+ ! loss ( precipitate by ! =mation ( complex ions betwe5 an ion ( ! precipitate & a compon5t ( ! wa%+ mixture 7see p4 #adh74 ,b :]ev] su* complications c be exclud$1 ! me?od is a desirable "o4 ,x has sometimes be5 recomm5d$ to wa% a precipitate ) a saturat$ aque\s solution ( ! precipitate itself1 9 place ( ) pure wat]4 ,x 0 reason$ t ! solution1 be+ already saturat$ ) ! salt1 w\ld n be able to dissolve any ( ! precipitate obta9$4 ,t is true2 b if a saturat$ solution ( a salt1 ,me,x1 is plac$ on a filt] /ill hold+ an excess ( ! precipitant1 i4e4 "o ( ! ions1 say ,x1 ( ! precipitate1 !n ?is excess may cause sup]saturation ( ! saturat$ wa%+ fluid & "s ( ! salt may be precipitat$ out ( ! wa%+ fluid4 ,! me?od1 z commonly employ$1 has !re=e ! inh]5t fault1 !oretically at lea/1 ( be+ liable to give too high results4 ,if x is to be employ$ )\t error1 precautions mu/ be tak5 fir/ to remove1 f ! precipitate & filt]1 ! "m liquor 7conta9+ ! excess ( precipitant7 z completely z possible4 ,if 9 a giv5 case ?is c be accompli%$1 !n ! dang] ( precipitat+ any ( ! salt 7,me,x7 f ! saturat$ solution is avoid$1 & ! precipitate 7,me,x 7 may !n be fur!r wa%$ ) a saturat$ solution ( ! same salt 7,me,x71 ) advantage1 9 c]ta9 cases4 ,?us1 9 ! ,l9do-,gladd+ me?od#cad ( det]m9+ potassium 9 ! =m ( potassium *loroplat9ate1 ! s\rce ( error1 j discuss$1 has be5 avoid$ 9 ! foll[+ way3 ! excess ( precipitant1 *loroplat9ic acid ,h#b,pt,cl#f1 :i* has ! ion ,pt,cl#fb 9 common ) ! precipitate1 is fir/ remov$ f ! precipitate by ?or\gh wa%+ ( ! precipitate ) alcohol2 subsequ5tly1 o!r impurities1 e4g4 sulphates1 soluble 9 wat] b n 9 alcohol1 are wa%$ out ) an aque\s solution ( ammonium *loride#cae t has be5 saturat$ ) potassium *loroplat9ate4 ,! me?od gives good results4 ,! ,solubility-,product 9 ,volumetric ,analysis4--,a f9al in/ance ( ! application ( ! solubility-product pr9ciple to ! ord9>y me?ods ( analytical *emi/ry1 may be tak5 f ! field ( quantitative1 volumetric analysis4 ,a p>ticul>ly accurate me?od ( det]m9+ silv] consi/s 9 precipitat+ x z silv] *loride by means ( a /&>diz$ solution ( sodium *loride4 ,! aim ( ! me?od is to recognize1 z exactly z p#aej possible1 ! po9t :]e ! action ,ag,n,o#c ,na,cl ,ag,cl ,na,n,o#c has j complet$ itself1 i4e4 :]e "o equival5t ( sodium *loride has be5 add$ = j "o equival5t ( silv] nitrate pres5t4 ,a v s5sitive me?od#caf dep5ds on ! fact t silv] *loride c be made to coagulate by ! vigor\s %ak+ ( its susp5sions1 & t ! coagulat$ *loride settles rapidly1 leav+ a cle> sup]natant liquid1 9 :i* ! appe>ance ( ! fa9te/ turbidity may be recogniz$1 :5 ! sodium *loride solution is c>efully add$ to ! silv] nitrate solution "u inve/igation4 ,n[1 :5 sodium *loride solution is add$ 9 ?is way to silv] nitrate1 a po9t is rea*$ 7call$ ! neutral po9t71#cag :]e ! addition ( a fur!r drop or two ( sodium *loride solution w /ill produce a precipitate1 & :]e "o w\ld be incl9$ to decide t too little ( ! *loride _h be5 us$ to complete ! action4 ,b1 at ! same "t1 ! addition ( a few drops ( silv] nitrate solution to ! solution at ! neutral po9t also produces a precipitate ( silv] *loride1 seem+ly indicat+ t an excess ( sodium *loride _h be5 us$1 & app>5tly contradict+ ! previ\s result4 ,z a matt] ( fact1 su* a behavior is exactly :at is to be expect$ f a solution1 :5 exactly equival5t quantities ( silv] nitrate & sodium *loride h be5 br\ght toge!r 9 solution4 ,! solution is !n saturat$ ) silv] *loride1 ,k,s4,p4 ,ag ,cl & ,ag ,cl1 & ! fur!r addition ei!r ( ! silv]-ion 7silv] nitrate7 or ( ! *loride-ion 7sodium *loride7 %\ld produce a precipitate1 accord+ to ! pr9ciple ( ! solubility-product4 ,! correct end-po9t 9 ! det]m9ation is1 ?us1 ! neutral po9t1 = at t po9t ! quantity ( silv] pres5t is equival5t to ! quantity ( sodium *loride add$4 ,effect ( ,electrolytes ) ,no ,ion 9 ,common ) ! ,precipitate4--,9 ! precipitation ( silv] acetate f its saturat$ solution by ! addition ( sodium acetate 7p4 #ade71 x is ! acetate-ion1 accord+ to ! pr9ciple ( ! solubility-product1 :i* is effective--! sodium-ion has no "p 9 ! action4 ,also1 9 a simil> way1 ! precipitation produc$ by ! addition ( silv] nitrate is ascrib$ to ! increas$ conc5tration ( ! silv]-ion--! nitrate-ion has no %>e 9 ! action4 ,we may ask1 :at ! effect on ! solubility ( silv] acetate w be1 if a salt1 sodium nitrate1 yield+ only =eign ions1 & no common "o1 is add$ to its saturat$ solution4 ,! pres5ce ( sodium & ( nitrate ions w n increase ! conc5tration ( ei!r ( ! ions ( silv] acetate1 w n increase ! value ( ei!r factor 9 ! product ( ion conc5trations2 ! addition ( sodium nitrate1 !re=e1 %\ld n lead to ! precipitation ( any silv] acetate1 & z a matt] ( exp]im5t x does n 7exp474 ,a clos] /udy p#aea ( ! conditions w %[1 9 fact1 t x r5d]s silv] acetate some:at m soluble4 ,! addition ( ! sodium-ion w lead to ! suppression ( "s ( ! acetate-ion1 nonioniz$ sodium acetate be+ =m$ to a c]ta9 ext5t2 ! nitrate-ion w comb9e ) "s ( ! silv]-ion to =m nonioniz$ silv] nitrate3 ?us ! conc5trations ( bo? ( ! ions ( silv] acetate are r$uc$1 & ! product ( ion conc5trations is r5d]$ small] ?an ! solubility-product con/ant1 7,,*#c;,,coo x7 7,ag y7 ,k,s4,p44 ,s9ce ! conc5trations ( bo? ! silv] & ! acetate ions are r$uc$1 !y w n comb9e z rapidly z be=e to =m nonioniz$ silv] acetate1 & ! conditions ( equilibrium betwe5 ! latt] & its ions mu/ be di/urb$4 ,! nonioniz$ salt ionizes1 = a mom5t1 m rapidly ?an x is =m$ & its conc5tration w ?us be r$uc$4 ,we1 !re=e1 might expect ! solution to become unsaturat$ 9 respect to ! nonioniz$ =m1 & ! solid salt1 if pres5t1 %\ld g into solution4 ,9 o!r words1 ! addition ( a salt ) two =eign ions %\ld increase ! solubility ( a difficultly soluble salt 7x is und]/ood t no salt is us$ :i* w\ld precipitate a new1 less soluble salt74 ,?is expectation has also be5 fully confirm$ by c>eful quantitative det]m9ations1 especially by ,a4 ,a4 ,noyes & 8 collaborators4 ,! effect may be demon/rat$ m easily by ! addition to silv] acetate ( an electrolyte :i* w v ?or\ghly suppress "o ( its ions4 ,nitric acid is su* an ag5t4 ,! hydrog5-ion w v decid$ly r$uce ! conc5tration ( ! acetate-ion1 acetic acid be+ a weak acid 7table1 p4 #ajd74 ,!re is no difficulty 9 recogniz+ ! anticipat$ effect 7exp474 ,solution ( ,precipitates4--,we f9d1 !n1 t :5 ! product ( ! ion conc5trations ( a difficultly soluble salt becomes small] ?an ! solubility-product con/ant1 ! solution is unsaturat$ 9 reg>d to ! salt1 & ! solid salt1 if pres5t1 w g into solution4 ,summ>y4--,! conclusions conc]n+ ! application ( ! solubility-product con/ant may be summ>iz$ z foll[s3 ,a solution is saturat$ ) a difficultly soluble ionog5 :5 ! product ( ! conc5trations ( ! ions ( ! ionog5 is equal to ! *>act]i/ic solubility-product con/ant 7at ! giv5 temp]ature74 ,a solution is sup]saturat$ & precipitation w foll[1 if ! product ( ! ion conc5trations is great] ?an ! con/ant4 p#aeb 7,see p4 #abb 9 reg>d to precautions aga9/ prolong$ sup]saturation47 ,a solution is unsaturat$1 & ! ionog51 if pres5t1 w dissolve :5 ! product ( ! ion conc5trations is small] ?an ! con/ant4 ,fur!r ,consid]ations ,conc]n+ ,precipitation & ,solution4--,x is fur!r evid5t t precipitation is favor$1 if ! precipitat+ ag5t conta9s an electrolyte :i* produces ! precipitat+ ion readily2 = in/ance1 c>bonic acid does n precipitate any b>ium c>bonate f a solution ( b>ium *loride 7exp47--c>bonic acid be+ an exce$+ly weak acid & produc+ only a m9ute conc5tration ( ! c>bonate-ion ,,co#cb1 necess>y = ! precipitation2 b sodium c>bonate1 a readily ioniz$ salt1 w precipitate ! b>ium c>bonate quantitatively 7p4 #ij74 ,if "s alkali is add$ to ! mixture ( b>ium *loride & c>bonic acid 7exp471 ! latt] is conv]t$ into a readily ioniz$ salt1 ! conc5tration ( ! c>bonate-ion is ?us decid$ly increas$1 & ! precipitate =ms in/antly4 ,9 ! same way1 if hydrog5 sulphide--a /ill weak] acid 7table1 p4 #ajd71 :i* =ms only m9ute quantities ( sulphide & hydrosulphide ions 7,s#b & ,,hs7--is pass$ ?r\gh a solution ( f]r\s sulphate1 x fails to precipitate f]r\s sulphide2 b a salt ( hydrog5 sulphide1 ammonium sulphide1 = in/ance1 precipitates f]r\s sulphide quantitatively 7exp474 ,on ! o!r h&1 solution ( an ionog5 is evid5tly favor$ & its precipitation r5d]$ m difficult1 if we suppress "o 7or bo?7 ( its ions4 ,?us b>ium phosphate1 calcium c>bonate1 silv] borate1 & _m salts ( weak acids1 t are v difficultly soluble 9 wat]1 are q easily soluble 9 /rong acids1 :i* suppress ! anions by conv]t+ !m into little ioniz$ acids4 ,:5 a precipitate is dissolv$ by ! addition ( a reag5t1 su* z an acid1 an alkali1 ammonia1 ammonium sulphide--*emical solv5ts mo/ frequ5tly us$ 9 analytical "w--we may1 z a g5]al pr9ciple1 consid] t ! reag5t mu/ affect "o or bo? ( ! ions ( ! precipitate 9 "q1 suppress+ x 7or !m7 & !reby mak+ solution possible4 ,! problem ( det]m9+ 9 :at way ! suppression ( ! ion is effect$1 mu/ !n be fac$4 ,_m occasions to det]m9e su* que/ions#cah w arise4 p#aec ,we h1 !re=e1 a c]ta9 degree ( control ov] ! precipitation & solution ( electrolytes1 ! control dep5d+ ^u1 & be+ limit$ by1 ! fact t ! factors ( ! product ( ion conc5trations are v>iables4 ,on ! o!r h&1 we h little control1 9 a giv5 solv5t1 ov] ! "q ( solution or precipitation z affect$ by ! value ( ! ion product con/ant1 ! rema9+ t]m 9 ! equation ( ! solubility-product = saturat$ solutions4 ,^! con/ants cov] a v wide range ( values = ! v>i\s salts1 :i* are mo/ frequ5tly us$ 9 analytical "w = ! precipitation ( ! common ions4#cai ,!y are subject to v>iation ) ! temp]ature1 &1 z a rule1 z mo/ salts are m soluble at high] ?an at l[] temp]atures1 ! values ( ! con/ants increase ) ! temp]ature4 ,= exce$+ly difficultly soluble salts1 ! increase is commonly ( no practical mom5t 9 analytical "w1 :51 by an excess ( ! precipitant1 ! ion1 :i* is to be precipitat$1 c be precipitat$ quantitatively2 ! solubility ( ! nonioniz$ salt1 t is precipitat$1 is s m9ute 7see p4 #adh7 9 ?is case1 ev5 at high temp]atures1 t x is altoge!r negligible = ord9>y purposes4#cbj ,on ! o!r h&1 precipitates are (t5 us$ :i* are n at all extremely insoluble b m]ely r difficultly soluble2 !y are us$ 9 spite ( _! relatively slight insolubility because !y are ! be/ available =ms = our purposes4 ,su* salts are1 = in/ance1 lead *loride1 magnesium-ammonium phosphate1 potassium *loroplat9ate4 ,:5 ^! are precipitat$1 n only mu/ ! fact t !y are appreciably soluble at ord9>y temp]ature be tak5 into acc\nt1 b also ! fact t !y are v mu* m soluble at high] temp]atures4 ,lead *loride & potassium *loroplat9ate are1 = in/ance1 q soluble 9 hot wat]4 ,z a rule1 we select = ! =m 9 :i* a giv5 ion is to be precipitat$1 a =m :i*1 9 a saturat$ aque\s solution1 %[s ! smalle/ conc5tration ( ! ion 9 "q4 ,b if no =m is p#aed kn[n :i* is suffici5tly insoluble to give satisfactory quantitative results1 !n we h rec\rse to a *ange 9 ! solv5t4 ,solubility & ,solv5t4--,= in/ance1 a mixture ( alcohol & wat] may be us$1 or wat] be exclud$ altoge!r2 & ei!r absolute 7wat]-free7 alcohol or a mixture ( alcohol & e!r may be employ$4 ,9 ! quantitative treatm5t ( potassium *loroplat9ate1 ! la/-nam$ mixture is us$ 9 place ( wat]4 ,! *ange ( solv5t affects ! solubility by a *ange bo? 9 ! solubility ( ! ioniz$ portion ( a salt & 9 t ( ! nonioniz$ salt4 ,an important quantitative relation betwe5 ! solubility ( a giv5 ionog5 9 diff]5t solv5ts & ! ioniz+ p[]s ( ! solv5ts1 z det]m9$ by _! dielectric con/ants 7p4 #fc71 0 pr$ict$1 on ! basis ( !oretical consid]ations1 by ,mal/rm#cba & by ,baur4#cbb ,wald5#cbc has furni%$ exp]im5tal confirmation ( ! relation3 ,! degree ( ionization ( a salt is f\nd to be ! same 9 its saturat$ solutions 9 diff]5t solv5ts1 :5 ! solutions are saturat$ at ! same temp]ature4 ,if ?is relation is comb9$ ) t discuss$ on page #fc1 accord+ to :i* ! degree ( ionization ( a giv5 salt1 9 diff]5t solv5ts1 is ! same1 :5 ! cube roots ( its conc5trations are directly proportional to ! dielectric con/ants ( ! solv5ts 7e#a 3 c#a e#b 3 c#b a con/ant71 !n we f9d1 t 9 saturat$ solutions ( a giv5 salt1 9 diff]5t solv5ts1 ! cube roots ( ! conc5trations1 or solubilities1 are directly proportional to ! dielectric con/ants ( ! solv5ts1 or1 ! solubilities are proportional to ! ?ird p[]s ( ! dielectric con/ants4 e#a 3 c#a e#b 3c#b a con/ant1 or e#ac 3 e#bc c#a 3 c#b1 c#a & c#b repres5t+ ! solubilities1 9 mol> conc5trations1 9 two solv5ts ( dielectric con/ants e#a & e#b4 ,! foll[+ table illu/rates ! relations = a salt exam9$ by ,wald51 a d]ivative ( ammonium iodide1 namely tetrae?yl ammonium iodide 7,c#b;,h#e7d,,ni4 ,! fir/ column gives ! "n ( ! solv5t1 ! second ! solubility or conc5tration 9 ! saturat$ solution1 9 t]ms ( ! proportion ( moles ( ! solute to ! total numb] ( moles pres5t#cbd p#aee 7solute solv5t72 ! ?ird column gives ! dielectric con/ant1 "u comp>able conditions1 & ! la/ column gives ! relation e 3 c4 ,solv5t4 ,solubility4 e#e e 3 c ,wat] #j4jccb #ge4j #ej4e ,nitrob5z5e #j4jjbj #cb4b #ed4h ,e?yl alcohol #j4jjbja #bf4f #de4e ,acetone #j4jjjgb #ba4h #eb4h ,amyl alcohol #j4jjjca #ae4j #dh4 ,9 view ( ! difficulties 9 det]m9+ ! values = ! dielectric con/ant1 ! agreem5t 9 ! values ( ! la/ column mu/ be consid]$ satisfactory4#cbe ,?is important pr9ciple =ms ano!r /rik+ in/ance ( ! supreme influ5ce ( electrical relations 9 det]m9+ ! behavior ( ionog5s 9 solution 7see p4 #aaa74 ,s9ce1 9 solutions saturat$ at ! same temp]ature ) a giv5 ionog51 ! degree ( ionization ( ! ionog5 is ! same 9 bo? solv5ts1 ! proportion ( nonioniz$ to ioniz$ salt is also ! same4 ,if a salt1 e4g4 calcium sulphate1 is less soluble 9 alcohol ?an 9 wat]1 ! alcohol mu/ hold less ( ! nonioniz$ =m1 z well z less ( ! ioniz$ salt1 ?an does an equal volume ( wat] at ! same temp]ature4 ,! developm5t ( fur!r relations1 ( fundam5tal importance to analytical *emi/ry1 ) ! aid ( ! laws ( *emical & physical equilibrium & ( ! pr9ciple ( ! solubility-product1 w be tak5 up 9 ! /udy ( ! reactions ( ! v>i\s analytical gr\ps ( ions4 ,,footnotes3 #bia ,z4 phys4 ,*em41 #d1 #cgb 7#ahhi74 ,see also van 't ,h(f1 ibid41 #c1 #dhd 7#ahhi74 #bib ,cf4 page #id4 #bic ,a4 ,a4 ,noyes1 ,z4 phys4 ,*em41 #i1 #fah 7#ahib72 ,f9dlay1 ibid41 #cd1 #dji 7#aijj74 #bid ,z =eign salts affect ! ionization ( poor electrolytes 7p4 #aji71 ! ratio ( equation ,i w\ld hold z little = poor electrolytes1 & w\ld gr[ l>g] ) an increas$ conc5tration ( ! =eign salts4 #bie ,cf4 ,a4 ,a4 ,noyes1 ,congress ( ,arts & ,sci5ces 7,/4 ,l\is71 #d1 #cba 7#aijd7 & ,/ieglitz1 ,j4 ,am4 ,*em4 ,soc41 #cj1 #idf 7#aijh7 7,/ud471 & ! ref]5ces to lit]ature giv5 !re4 ,! empirical relation seems to hold = dilute solutions1 ! total electrolyte conc5tration ( :i* is n great] ?an #j4b to #j4c gram-equival5t p] lit]1 &1 r\ghly1 = conc5trations n great] ?an #j4e gram-equival5t p] lit]4 #bif ,see ,/ieglitz1 loc4 cit4 #big ,s9ce ! writ+ ( ?is x has be5 le>n$ t su* inve/igations h be5 c>ri$ out by ,h>k9s4 ,cf4 ,j4 ,am4 ,*em4 ,soc41 #aiaa4 #bih ,j4 ,am4 ,*em4 ,soc41 #cb1 #dhh 7#aiaj74 #bii ,o!rwise a p]petuum mobile ( ! second class 7footnote #c1 p4 #ab7 c\ld be con/ruct$1 :i* is at v>iance ) exp]i5ce4 #cjj ,?is s5t5ce is quot$ f a lett] f ,dr4 ,wa%burn1 :o is at pres5t inve/igat+ mod]ately conc5trat$ solutions ( electrolytes1 to det]m9e ! range ( conc5trations 9 :i* x is possible to apply ! laws ( ideal solution4 #cja ,cf4 ,geffck51 ,z4 ,phys4 ,*em41 #di1 #beg 7#aijg71 & ! ref]5ces giv5 !re4 #cjb ,cf4 ,arrh5ius1 loc4 cit41 & simil> inve/igations on ! salt effect 7p4 #aji74 #cjc ,vide ,geffck51 loc4 cit41 #bie1 & ,/ieglitz1 loc4 cit41 & p4 #adb4 #cjd ,see also ,hill1 ,j4 ,am4 ,*em4 ,soc41 #cb1 #aahf 7#aiaj74 ,hill attacks ! pr9ciple z a :ole1 b br+s no evid5ce aga9/ its validity = solutions ( conc5trations up to #j4c4 #cje ,! limit ( conc5tration dep5ds1 = con/ancy1 ^u ! nature ( ! salts4 ,! calculations1 on :i* ! data 9 ! tables on pp4 #adf-g are bas$1 involve extrapolations :i* prev5t ! results1 especially = ! m conc5trat$ solutions1 be+ consid]$ z f9al4 #cjf ,= fur!r illu/rations1 vide ,/ieglitz1 ,j4 ,am4 ,*em4 ,soc41 #cj1 p4 #idg 7#aijh71 & ! ref]5ces giv5 !re to ! "w ( ,noyes1 ,f9dlay1 etc4 #cjg ,"s in/ances are kn[n :]e ! solubility ( a salt is increas$ by ! addition ( a salt ) a common ion4 ,9 su* cases x is extremely likely t an ion ( ! salt 9 "q =ms a complex ion ) a compon5t ( ! solution4 ,vide ,a4 ,a4 ,noyes1 ,z4 phys4 ,*em41 #f1 #bda 7#ahij71 & #i1 #fjc 7#ahib74 ,9 ,*apt] ,,xii we %all discuss1 9 detail1 in/ances ( ?is nature :]e ! =mation ( complex ions is p>ticul>ly susceptible ( exact exp]im5tal v]ification4 #cjh ,especially by ,noyes1 loc4 cit41 & lat] pap]s2 ,f9dlay1 loc4 cit4 #cji ,?is is ! value = a simil> ratio = ,k,cl ( ! same conc5tration z f\nd1 by extrapolation1 f ! data 9 ! table on p4 #ajh4 #caj ,ow+ to ! possibility ( ! =mation ( complex ions 7,*apt] ,,xii71 ea* individual case mu/ be consid]$ by itself & ! mo/ favorable conditions = ! complete precipitation det]m9$ exp]im5tally4 ,! rule m5tion$ is to be us$ z a guide1 & ! ref]5ce to ! possibility ( ! =mation ( complex ions consid]$ z a w>n+1 9 ! plann+ ( su* inve/igations4 #caa ,cf4 p4 #acf1 conc]n+ precautions us$ to prev5t precipitates f assum+ ! colloidal /ate4 #cab ,fres5ius1 ,quantitative ,analysis1 ,i1 #cee 7#aijd74 #cac ,ibid41 ,i1 #cjg4 #cad ,(ficial ,me?ods ( ,analysis1 ,bullet9 #ajg1 p4 #aa1 ,u4 ,s4 ,dept4 ( ,agriculture4 #cae ,! excess ( *loroplat9ic acid is fir/ wa%$ out ( ! precipitate prim>ily to avoid subsequ5t precipitation ( ammonium *loroplat9ate1 b its removal also avoids ! error discuss$ 9 ! text4 #caf ,gay-,lussac's me?od4 #cag ,muld]4 ,see ,sutton's ,volumetric ,analysis1 p4 #cjd 7#aijd74 #cah ,vide ,*apt]s ,,xii & ,,xiii4 #cai ,a table ( exact solubilities is giv5 at ! end ( ! ,lab4 ,manual1 q4v4 #cbj ,9 ! mo/ exact quantitative "w1 z dem&$ 9 ! det]m9ations ( atomic weights1 e kn[n loss mu/1 z f> z possible1 be measur$ & tak5 into acc\nt4 ,beautiful in/ances ( su* "w are f\nd 9 ,t4 ,w4 ,ri*>ds' classic det]m9ations ( atomic weights4 ,see1 = in/ance1 ,ri*>ds1 ,c>negie ,in/itution ,publications1 ,no4 #abe 7#aiaj71 ,det]m9ations ( ! ,atomic ,weights ( ,silv]1 ,li?ium & ,*lor9e 7,/ud474 #cba ,z4 ,elektro*em41 #aa1 #gig 7#aije74 #cbb ,ibid41 #aa1 #icf 7#aije71 & #ab1 #gbe 7#aijf74 #cbc ,z4 phys4 ,*em41 #ee1 #gjg 7#aijf71 & #fa1 #fch 7#aijg74 #cbd ,if n is ! numb] ( moles ( solute dissolv$ 9 ,n moles ( solute1 ! conc5tration ( ! solute may be express$ z n _/ 7n ,n71 :i* is call$ its mole fraction4 ,?is =m ( express+ conc5trations is 9 _m p>ticul>s pref]able to ! mole _/ lit] =m4 ,= v dilute solutions 7n is v small comp>$ ) ,n7 ! two =ms become practically id5tical1 b !y are n s = m conc5trat$ solutions1 & ! mole-fraction expression is !n easi] to treat rigor\sly4 #cbe ,see ,wald51 loc cit41 = m ext5d$ data4 p#aeg ,,"p ,,ii ,,sy/ematic ,,analysis ,,& ,,! ,,application ,,( ,,fundam5tal ,,pr9ciples ,,*apt] ,,ix ,,sy/ematic ,,analysis ,,= ,,! ,,common ,,metal ,,ions4 ,,! ,,ions ,,( ,,! ,,alkalies ,,& ,,( ,,! ,,alkal9e ,,e>?s4 ,,ord] ,,( ,,precipitation ,,( ,,difficultly ,,soluble ,,salts ,,) ,a ,,common ,,ion ,9 sy/ematic analysis x is mo/ conv5i5t to make sep>ate exam9ations = ! metal & = ! acid ions4 ,! exam9ation = metal ions usually prec$es t = ! acid ions1 & ! s*eme ( analysis = ! =m] w be consid]$ fir/4 ,! analytical gr\p+ ( ! metallic elem5ts is n a natural "o1 z f> z _! *emical behavior is conc]n$4 ,su* a gr\p+ is f\nd 9 ! ,p]iodic ,sy/em ( ,m5deleff & is us$ 9 sy/ematic inorganic *emi/ry4#cbf ,! gr\ps 9 analysis are bas$ *iefly1 b n exclusively1 on ! physical prop]ty ( great] or small] solubility ( c]ta9 salts ( ! metals4 ,accord+ to ! salts *os51 diff]5t sy/ems v>y some:at 9 detail4 ,frequ5tly elem5ts ( ! same natural family are also f\nd 9 ! same analytical gr\p1 relation%ip 9 *emical prop]ties be+ (t5 co9cid5t ) relation%ip 9 ! physical behavior ( ! salts ( ! metals4 ,9 ! foll[+ li/1 ! common metal ions are arrang$ 9 gr\ps1 :i* are giv5 9 ! ord] 9 :i* !y are precipitat$ 9 ! me?od ( sy/ematic analysis adopt$4 ,9 ea* case1 a gr\p "n & ! *>act]i/ic reag5ts us$ 9 sep>at+ a gr\p f ^? foll[+ x1 are giv54 ,! ,silv] ,gr\p4--,ions ^: *lorides are insoluble 9 dilute acid solutions4 ,! precipitat+ ag5t is ,h,cl4 p#aeh ,pb#b 7! *loride is some:at soluble71 ,ag1 ,hg4 ,! ,copp] & ! ,ars5ic ,gr\ps4--,ions ^: sulphides are insoluble 9 dilute acids4 ,! precipitat+ ag5t = ! two gr\ps is ,h#b,s1 9 acid solution4 ,! sulphides ( ! ars5ic gr\p are soluble 9 a mixture ( 7,,nh#d7b,s & 7,,nh#d7b,sx & are sep>at$ !reby f ! sulphides ( ! copp] gr\p4 ,! ,copp] ,gr\p4--,hg#b1 7,pb#b71 ,bi#c1 ,cu#b1 ,cd#b4 ,! ,ars5ic ,gr\p4--,z#c1 ,z#e1 ,sb#c1 ,sb#e1 ,sn#b1 ,sn#d1 ,pt#b1 ,pt#d1 ,au1 ,au#c4 ,! ,alum9ium & ! ,z9c ,gr\ps4--,ions ^: sulphides or hydroxides are insoluble 9 neutral or slightly alkal9e 7ammonium hydroxide7 solutions4 ,! two gr\ps are precipitat$ toge!r by a mixture ( ,,nh#d;,cl1 ,,nh#d,,oh1 7,,nh#d7b,s4 ,! alum9ium gr\p may be sep>at$ f ! z9c gr\p by treatm5t ( solutions ( ! *lorides or nitrates ) b>ium c>bonate4 ,! ,alum9ium ,gr\p4--,fe#c1 ,al#c1 ,cr#c4 ,! ,z9c ,gr\p4--,fe#b1 ,ni#b1 ,co#b1 ,mn#b1 ,zn#b4 ,! ,alkal9e ,e>? ,gr\p4--,ions ^: c>bonates & phosphates are insoluble 9 neutral or alkal9e solutions4 ,! precipitat+ ag5t is ,,nh#d;,cl1 ,,nh#d,,oh1 7,,nh#d7b;,,co#c = ,ba#b1 ,sr#b1 ,ca#b1 & 7,,nh#d7b;,,hpo#d = ,mg#b4cbg ,! ,alkalies4--,ions ^: *lorides1 sulphides1 hydroxides1 c>bonates & phosphates are soluble4 ,k1 ,na1 ,,nh#d4 ,9 consid]+ ! analytical reactions & ! analysis ( ^! gr\ps ( metal ions1 we %all take up ! gr\ps 9 ! ord] rev]s$ to t giv5 9 ! table4 ,we %all beg9 ) ! gr\p ( alkali metals1 foll[ ?is gr\p ) ! alkal9e e>?s1 !n take ! alum9ium & z9c gr\ps1 ! copp] & silv] gr\ps1 & f9i% ) ! ars5ic gr\p4 ,?is ord] is *os5 because ! *emi/ry ( ! reactions involv$ is simple/ 9 ! gr\ps to be /udi$ fir/ & gr[s m complicat$ z we advance to ^? to be /udi$ lat]4 ,x is n int5d$ to discuss 9 detail all ! reactions & me?ods2 our att5tion w be limit$ r to ! /udy ( typical g5]al relations1 & ! /ud5t is expect$ to acquire ! p[] to apply ! g5]al conclusions rea*$1 to any specific case dem&+ x4 p#aei ,! ,alkali ,gr\p4--,! gr\p includes ! ions ( sodium & potassium1 ! mo/ common & mo/ important ( ! alkali metals1 & ! ammonium-ion4 ,*>act]i/ic ( ! ions ( ! gr\p is ! fact t all ( _! common salts are easily soluble 9 wat]4 ,!y rema9 9 solution 9 sy/ematic analysis1 :ile o!r metal ions are remov$ 9 ! =m ( v>i\s insoluble precipitates4 ,! ammonium-ion is recogniz$1 & may be remov$ f a mixture ( ! salts ( ! gr\p1 on ! basis ( a fundam5tal di/9ction 9 its *emical behavior1 namely its in/ability & ! in/ability ( its comp\nds4 ,sodium-ion & potassium-ion1 are recogniz$1 & sep>at$ f ea* o!r1 by physical me?ods4 ,all ammonium comp\nds1 ,,nh#d,x1 decompose m or less readily into ammonia & ! free acids1#cbh accord+ to ! rev]sible reaction1 ,,nh#d,x ,,nh#c ,,hx4 ,! /rong] ! acid comb9$ ) ammonia1 ! m /able is ! salt1 & ! high] is ! temp]ature1 at :i* ! salt decomposes readily & rapidly4 ,ammonium *loride1 "o ( ! mo/ /able ( ! salts1 is decompos$ rapidly only at ab\t #cej1 :i* is1 h[ev]1 /ill bel[ r$ heat2 ammonium c>bonate1 ! salt ( a v mu* weak] acid1 decomposes appreciably at ord9>y temp]atures1 & expos$ to ! air1 x gradually disappe>s z ammonia1 c>bon dioxide & wat]4 ,if ! acid ( ! salt is volatile at ! dissociation temp]ature ( ! salt1 ! :ole salt is volatiliz$1 & if ! ammonia & volatile acid vapor rea* a cold] space1 recomb9ation to =m ! orig9al solid salt occurs to a consid]able ext5t 7! smok+ (f ( ammonium *loride74 ,if ! acid is n volatile1 ! salt1 nev]!less1 loses its ammonia at temp]atures bel[ r$ heat1 :ile ! acid rema9s4 ,sodium-ammonium phosphate1 = in/ance1 :5 heat$1 loses its ammonia1 & sodium-dihydrog5 phosphate is left z a nonvolatile residue4 ,ammonium happ5s to =m salts :i* closely resemble ! correspond+ salts ( potassium 9 physical prop]ties1 su* z p#afj solubility & insolubility1 salts :i* c\ld readily be mi/ak5 = potassium salts4 ,advantage is tak5 ( ! *emical in/ability ( ! ammonium salts1 j describ$1 to remove ammonium completely f mixtures1 by ignition1 be=e te/s = potassium are made4 ,wat] is a f> weak] acid 7see table1 p4 #ajd7 ?an c>bonic acid & x is n surpris+ to f9d ! comp\nd =m$ by wat] & ammonia1 ammonium hydroxide1 "o ( ! lea/ /able ( ! ammonium comp\nds4 ,ev5 at ord9>y temp]ature1 ! hydroxide is m or less decompos$1 accord+ to a rev]sible reaction ( ! same type z t f\nd = ! ammonium salts1 ,,nh#d,,oh ,,nh#c ,,hoh4 ,*emi/s h always be5 int]e/$ 9 ! problem ( ! exact degree ( /ability ( ammonium hydroxide1 &1 m p>ticul>ly1 9 ! problem :e!r ammonia gives solutions 9 wat] %[+ v mu* weak] basic /r5g?#cbi ?an equival5t solutions ( potassium & sodium hydroxides1 prim>ily because only a small proportion ( ! ammonia is comb9$ ) wat] to =m ! real base1 ammonium hydroxide 7:i* w\ld be pres5t !n 9 mu* m dilute solution ?an ! alkali metal hydroxides are 9 ! solutions ) :i* ! comp>ison is made71 or *iefly because ammonium hydroxide is mu* less readily ionizable ?an potassium or sodium hydroxide4 ,= ! rev]sible action ,,nh#c ,,hoh ,,nh#d,,oh we w\ld h1 at a con/ant temp]ature1 accord+ to ! law ( *emical equilibrium1 ,,nh#c ,,hoh _/ ,,nh#d,,oh k4 ,= a dilute solution at a giv5 temp]ature ! conc5tration ( ! wat] may be consid]$ a con/ant1 & !re=e ,,nh#c _/ ,,nh#d,,oh k _/ ,,hoh k,,nh#c4 7,i7 ,= ! ionization ( ammonium hydroxide1 ,,nh#d,,oh ,,nh#d ,,ho1 we w\ld h 9 turn1 ,,nh#d ,,ho _/ ,,nh#d,,oh kbase4 7,,ii7 ,?is con/ant repres5ts ! real ionization con/ant ( ammonium hydroxide z a base1 & its approximate value has only rec5tly be5 det]m9$ by ,moore#ccj & f\nd to be ab\t #e;,e#e4 ,! ratio ,,nh#c _/ ,,nh#d,,oh 0 f\nd to be approximately #b at #bj4 ,accord+ to ?is result1 ammonium hydroxide is really a mu* weak]1 less readily ioniz$ base ?an potassium or sodium hydroxide4 ,! effici5cy ( ammonium hydroxide z a base dep5ds p#afa on bo? conditions ( equilibrium2 ! fir/ equation /ates :at proportion ( ammonium hydroxide c exi/1 z su*1 9 solution1 if a giv5 am\nt ( ammonia is dissolv$ 9 a giv5 am\nt ( wat]1 & ! second equation %[s ! proportion ( ! hydroxide1 :i* is ioniz$4 ,! equations may be comb9$#cca into "o expression1 ,,nh#d ,,ho _/ 7,,nh#d,,oh ,,nh#c7 ,k4 7,,iii7 ,t is1 ! ratio ( ,,nh#d ,,ho to ! total conc5tration ( nonioniz$ ammonium hydroxide & ammonia1 is a con/ant4 ,?is con/ant has ! value #j4jjj1jah at #ah 7z giv5 9 ! table1 p4 #ajf7 &1 z said1 comprises 9 a s+le expression a /atem5t measur+ ! effici5cy1 z a base1 ( a solution ( ammonium hydroxide & ammonia 9 aque\s solutions4 ,! conc5tration ( ! hydroxide-ion1 on :i* ! effici5cy z a base dep5ds1 c be asc]ta9$ directly f ! expression1 provid$ we "k ! total conc5tration ( ! ammonia & ammonium hydroxide & ! conc5tration & degree ( ionization ( any ammonium salt1 :i* may be pres5t ) ! base 7see p4 #afa74 ,^! data are easily obta9$ by direct measurem5t4 ,! in/ability ( ammonium hydroxide is us$ z a means = detect+ ammonium-ion 9 its salts4 ,! latt] are treat$ ) "s /rong base1 su* z sodium or calcium hydroxide1 & ! ammonia1 lib]at$ by ! decomposition ( its hydroxide1 is recogniz$ by its odor or by ! m s5sitive te/ ( its action on moi/ litmus4 ,! delicacy ( ! te/ is dep5d5t on ! conditions express$ 9 ! equilibrium equation 7p4 #afj74 ,sodium & potassium resemble ea* o!r s pr(\ndly 9 ! *emical behavior ( _! comp\nds1 t !y are recogniz$1 & sep>at$ f ea* o!r1 by physical me?ods4 ,a v simple physical te/ is bas$ on ! color ( _! heat$ vapors1 ! color imp>t$ to ! nonlum9\s buns5 flame by ! introduction & volatilization ( _! salts4 ,! sodium flame is s int5se t1 if sodium is pres5t 9 any quantity1 ! color ( its flame easily masks ! fa9t color ( potassium vapor4 ,! color ( ! flame is be/ exam9$1 9 su* a case1 ) ! aid ( a spectroscope1 9 :i* ! light emitt$ by ! two elem5ts may be readily recogniz$ side by side1 or ) ! aid ( cobalt glass1 :i* absorbs ! sodium light4 p#afb ,! ions ( ! two metals may be sep>at$ & id5tifi$ by means ( difficultly soluble salts4 ,!re are s few ( ^! 9 ! case ( bo? ions1 t rec\rse mu/ be tak5 to ! salts ( comp>atively uncommon acids4 ,potassium *loroplat9ate ,k#b,pt,cl#f1 precipitat$ by ! addition ( *loroplat9ic acid ,h#b,pt,cl#f to conc5trat$ solutions ( potassium salts1 gives v satisfactory results1 bo? 9 qualitative & 9 quantitative "w4 ,! acid t>trate1 ,,khc#d;,h#d,o#f1 ! picrate1 ,,kc#f;,h#b,n#c,o#g1 & ! cobalt9itrite1 ,k#c;,co7,,no#b7f1ccb are difficultly soluble & are sometimes us$ to id5tify potassium-ion4 ,! correspond+ ammonium salts are also difficultly soluble & resemble ! potassium salts1 & ammonium-ion mu/ !re=e be remov$1 z /at$ above1 if pres5t1 be=e any ( ^! precipitates may be us$ = ! id5tification ( potassium-ion4 ,9 ! case ( sodium-ion1 rec\rse is tak5 to ! salt ( a /ill m uncommon acid2 pyroantimonate ( sodium1 ,na#b;,h#b,sb#b,o#g1 #f aq41 is suffici5tly difficultly soluble & *>act]i/ic to be us$ z a means ( id5tify+ sodium-ion4 ,! ,alkal9e ,e>? ,gr\p4--,?is gr\p includes magnesium1 calcium1 /rontium1 & b>ium4 ,*emically1 ! analog\s comp\nds ( ! f\r alkal9e e>?s resemble "o ano!r s mu*1 t physical diff]5ces alone are us$ 9 _! sep>ation & id5tification4 ,= qualitative "w1 ! colors ( _! heat$ vapors1#ccc especially :5 exam9$ 9 ! spectroscope1 give u s5sitive & reliable te/s = _! pres5ce4 ,! alkal9e e>? ions1 especially ! ions ( b>ium1 /rontium & calcium1 =m a great numb] ( insoluble salts1 :i* may be us$ to sep>ate !m f ea* o!r4 ,salts us$ = ?is purpose & ! me?ods ( employ+ !m are consid]$ 9 detail 9 ! laboratory "w 7see ,"p ,,iii74 ,"h "s g5]al pr9ciples1 only1 w be consid]$ 9 connection ) ! behavior ( "s ( ! mo/ important ( ! precipitates4 ,!re is a v wide range 9 ! degree ( ! insolubility ( su* precipitates z are us$ 9 analysis4 ,9 ! table at ! end ( ,"p ,,iv1 ! exact solubilities ( ! mo/ important p#afc precipitates ( ! alkal9e e>?s are giv51 = #ah1 9 grams & moles p] lit]4 ,! values are in/ructive 9 a numb] ( respects4 ,inspection ( ! table %[s :i* are ! lea/ soluble 79 mol> t]ms71 & !re=e ! be/ salts1 = precipitat+ b>ium1 /rontium & calcium1 9 ord] to insure ! use ( ! mo/ s5sitive te/s = ! ions ( ea* ( ^! metals4 ,x also %[s :i* salts mu/ be treat$ ) special precautions to escape error4 ,x is fur!r se51 t if ! c>bonates ( ^! alkal9e e>?s are precipitat$ by a mod]ate excess ( ammonium c>bonate1 ! addition ( a sulphate 7= in/ance ammonium sulphate71 to ! filtrate f ! precipitat$ c>bonates1 w only precipitate b>ium sulphate1 ! only sulphate ^: solubility 7& solubility-product7 is small] ?an t ( ! correspond+ c>bonate4 ,9 ! same way1 calcium oxalate is ! only oxalate ( ^! ?ree alkal9e e>?s t w be precipitat$ by ammonium oxalate 9 ! filtrate f ! c>bonates 7see ,"p ,,iii 9 reg>d to precautions aga9/ difficultly soluble d\ble oxalates ( magnesium74 ,aga91 calcium sulphate is ! only "o ( ! sulphates1 :i* is suffici5tly soluble 9 wat] to give an imm$iate heavy precipitate1 :5 ! sulphates are %ak5 = a few mom5ts ) wat] & ! filt]$ solution is treat$ ) a few drops ( ammonium oxalate solution4 ,fractional ,precipitation4#ccd--;,if sulphuric acid is add$ to a #j4e mol> solution ( ! *loride ei!r ( b>ium1 ( /rontium or ( calcium1 ! correspond+ sulphate is precipitat$4 ,we may ask :i* sulphate w be precipitat$ fir/1 :5 sulphuric acid is add$1 drop by drop1 to a solution conta9+ ! ?ree *lorides4 ,?is problem1 a case ( ! fractional precipitation ( salts conta9+ a common ion1 may be treat$ f ! po9t ( view ( ! solubility-product pr9ciple z foll[s1 ! problem be+ limit$1 = ! sake ( simplicity1 to only two ( ! sulphates1 ^? ( b>ium & /rontium4 ,= a saturat$ solution ( b>ium sulphate1#cce at #ah1 9 contact ) ! solid salt1 we h1 accord+ to ! pr9ciple ( ! solubility-product1 ,k,ba,s,o#d ,ba#b ,,s#db #a;,e#aj1 p#afd & = a saturat$ solution ( /rontium sulphate1 we h simil>ly#ccf ,k,sr,s,o#d ,sr#b ,,s#db #b4e;,e#g4 ,n[1 we may ask :at ! conditions are "u :i* bo? precipitates c be pres5t toge!r 9 a condition ( equilibrium ) a sup]natant saturat$ solution4 ,9 su* a solution we h simultane\sly ,k,ba,s,o#d ,ba#ba ,,s#dba1 ,k,sr,s,o#d ,sr#ba ,,s#dba4 ,new symbols1 ,ba#ba1 etc41 are us$ = express+ ! conc5trations1 z !y are n ! same z 9 ! pure aque\s solutions4 ,! mu* m soluble /rontium sulphate makes ! conc5tration ( ! sulphate-ion v mu* great] ?an x is 9 ! saturat$ solution ( pure b>ium sulphate & dim9i%es ! conc5tration ( ! b>ium-ion proportionately 7p4 #ade74 ,! conc5tration1 ,,s#dba1 ( ! sulphate-ion1 repres5t+ ! actual 7total7 conc5tration ( ! ion 9 ! solution saturat$ ) bo? salts1 appe>s 9 bo? ( ! new equations4 ,comb9+ ! two equations1 we h1 = ! condition ( equilibrium betwe5 ! two precipitates & ! sup]natant liquid1 ,ba#ba _/ ,sr#ba ,k,ba,s,o#d _/ ,k,sr,s,o#d #a _/ #bejj4 ,t is1 9 a solution 9 equilibrium ) bo? precipitates at #ah1 ! /rontium-ion mu/ be ab\t #bejj times z conc5trat$ z is ! b>ium-ion4 ,if we />t ) equival5t quantities ( b>ium & /rontium *lorides1 say 9 #j4a mol> solutions1 & gradually add sulphuric acid or ammonium sulphate1 b>ium sulphate w be precipitat$ alone1#ccg until ! /rontium-ion is 9 ! excess p#afe indicat$ by ! ratio giv54 ,aft] t1 /rontium sulphate w be precipitat$1 ) traces ( b>ium sulphate1 ! ratio express$ 9 ! equilibrium equation be+ ma9ta9$ 9 ! sup]natant liquid4 ,on ! o!r h&1 if we />t ) a solution conta9+ a v l>ge excess ( a /rontium salt1 m ?an is requir$ by ! equilibrium ratio1 !n /rontium sulphate w be precipitat$ fir/1 until ! ratio giv5 is rea*$4 ,ev5 %\ld ! m soluble salt be precipitat$ fir/ f a solution conta9+1 say1 equal conc5trations ( b>ium & /rontium ions1 x c\ld n rema9 9 equilibrium ) ! sup]natant liquid & w\ld be conv]t$ into ! less soluble "o1 be=e equilibrium 0 rea*$ 9 ! sy/em4 ,we c foll[ simil> relations1 exp]im5tally1 by us+ precipitates ( diff]5t colors4 ,silv] *romate ,ag#b;,cr,o#d is an int5sely r$ precipitate1 t is r difficultly soluble 9 wat] 7exp472 a lit] ( wat] dissolves#cch #j4jbeb gram or #h;,e#e mole at #ah4 ,! conc5tration ( ! silv]-ion 9 ! saturat$ solution is !n #j4jjjaf mole4#cci ,silv] *loride ,ag,cl1 a :ite salt1 is /ill less soluble 9 wat]1 a lit] ( wat] at #ah dissolv+ #j4jjacd gram or #a;,e#e mole1 & ! conc5tration ( ! silv]-ion 9 ! saturat$ solution is1 !re=e1 only #a;,e#e mole1 z comp>$ ) #a4f;,e#d 9 ! saturat$ silv] *romate solution4 ,if a mixture ( potassium *romate & potassium *loride1 conta9+ approximately equal 7#j4ja mol>7 conc5trations ( ! two salts1 is prep>$ & silv] nitrate solution add$1 drop by drop1 to ! mixture1 ! fir/ p]man5t precipitate is ! :ite silv] *loride 7exp474 ,h[ev]1 z ! silv] nitrate solution /rikes ! surface ( ! liquid1 a r$ precipitate ( ! *romate1 mix$ ) *loride1 is mom5t>ily se51 :]e ! silv] nitrate tempor>ily produces a local excess ( ! precipitant4 ,b ! r$ precipitate disappe>s rapidly & gives way to ! :ite precipitate ( ! less soluble *loride4 ,! quantitative relations1 :i* may be develop$ ) ! aid ( ! pr9ciple ( ! solubility-product 7see bel[71 are su* t1 if little *romate is us$1 x may s]ve z an p#aff indicator to det]m9e quantitatively ! mom5t :5 all ! *loride1 )9 ! limits ( all[$ quantitative error1 is precipitat$1 ! fir/ p]man5t t+e ( p9k 7solid ,ag#b;,cr,o#d71 mix$ ) ! yell[ color ( ! solution1 be+ us$ z ! indication t ! precipitation ( ! *loride is complete4 ,potassium *romate is us$ z a favorite indicator 9 quantitative analysis1 = ?is purpose4 ,! quantitative relations#cdj = ! precipitation may be develop$ z foll[s3 ,= a sup]natant liquid 9 :i* a precipitate ( silv] *romate j appe>s p]man5tly1 toge!r ) ! *loride1 i4e4 = ! condition ( saturation ) bo? silv] salts at #ah1 we h ,k,ag,cl ,ag ,cl 7#a;,e#e7b #a;,e#aj & ,k,ag#b;,cr,o#d ,ag#b ,cr,o#db 7#a4f;,e#d7b 7#h;,e#e7 #b;,e#ab1 & !re=e3 ,cl#b _/ ,cr,o#db 7,k,ag,cl7#b _/ ,k,ag#b;,cr,o#d 7#a;,e#aj7b _/ #b;,e#ab #a _/ #b;,e#h4 ,= a solution conta9+ "o or two drops 7#j4a c4c47 ( saturat$ potassium *romate solution p] #ajj c4c41 a proportion frequ5tly us$ 9 quantitative analysis1 ! conc5tration ( ! *romate-ion is approximately #b4e;,e#c & ! *loride-ion w consequ5tly be precipitat$ until ,cl #c;,e#f4 ,! *ief s\rce ( error 9 ! me?od1 !n1 w n be due to ! incomplet5ess ( ! prior precipitation ( ! *loride1 b r to ! use ( ! small excess ( silv] nitrate requir$ to precipitate suffici5t *romate to be visible4 ,?is error may be avoid$1 & is avoid$ 9 v accurate "w 7e4g4 9 wat] analysis71 by det]m9+1 9 a blank te/1 ! am\nt ( silv] nitrate requir$ to %[ ! *ange ( t9t ( a pure *romate solution ( ! conc5tration to be us$ 9 ! titration & by titrat+ to ?is t9t 9 ! det]m9ation ( ! *loride3 ! volume ( silv] nitrate 7e4g4 #j4b c4c4 ( a #j4ja mol> solution71 requir$ to produce ! t9t 9 ! blank te/1 is subtract$ f ! total volume ( silv] nitrate us$ 9 ! *loride det]m9ation4 ,we f9d ?us1 t ! ord] ( precipitation ( difficultly soluble salts1 :i* conta9 a common ion 7fractional precipitation71 is subject to ! equilibrium conditions d]iv$ f ! application ( ! pr9ciple ( ! solubility-product to ! salts 9 "q4#cda ,x %\ld be fur!r not$ t ! condition ( equilibrium betwe5 two precipitates1 conta9+ a common ion1 & a sup]natant liquid1 dep5ds on ! conc5trations 9 ! sup]natant liquid1 9 ! liquid phase1 & n on ! quantities ( ! solids p#afg pres5t4 ,?is conclusion 0 fir/ rea*$ by ,guldb]g & ,waage1 to :om we owe ! law ( mass action1 & 0 fully confirm$ by !m4 ,! mod]n treatm5t ( ! subject sub/itutes ion conc5trations1 i4e4 ! conc5trations ( ! active compon5ts1#cdb = ! total conc5trations us$ by ^! inve/igators4#cdc ,t ! condition ( equilibrium is dep5d5t on ! liquid phase c easily be demon/rat$ if m]cur\s *loride & m]cur\s hydroxide are select$ z ! two precipitates1 9 ord] t we may foll[ *anges ( conc5tration 9 ! liquid phase by color *anges4 ,= ! condition ( equilibrium betwe5 ! two precipitates & ! sup]natant liquid we may develop ! relation ,,oh _/ ,cl ,k,hg,o,h _/ ,k,hg,cl ,k4 ,,exp4 ,a few drops ( ph5olph?alen are add$ to #ajj c4c4 ( a v dilute solution ( potassium hydroxide 7#a _/ #ejj mol>72 ! usual indication ( ! pres5ce ( ! hydroxide-ion is %[n & ! int5sity ( ! color w be a measure ( its conc5tration4 ,?ree id5tical solutions are prep>$ & !n a p9* ( calomel is add$ to two ( ! solutions1--_! p9k color fades decid$ly4 ,"s ( ! calomel is decompos$ into d>k-color$ m]cur\s oxide1 :i* is precipitat$1 & suffici5t potassium *loride is =m$ to br+ ! ratio ,,oh _/ ,cl1 9 ! solution1 d[n to ! value requir$ by ! con/ant ,k4 ,s9ce no *loride-ion is pres5t at ! />t1 ?is result c be br\ght ab\t only by ! *ange indicat$4 ,n[1 "s *loride1 say a little ( a conc5trat$ solution ( potassium *loride1 :i* reacts p]fectly neutral1 is add$ to "o ( ! mixtures ( ! hydroxide & *loride4 ,! conc5tration ( ! *loride-ion is increas$ 9 ! solution1 ! ratio ,,oh _/ ,cl is made mu* too small & ! condition ( equilibrium is di/urb$4 ,consequ5tly1 m]cur\s oxide reacts ) potassium *loride1 z express$ 9 ! equation ,hg,o,h ,k,cl ,hg,cl ,,koh1 until ! ratio ,,oh _/ ,cl p#afh has ! value requir$ by ! con/ant ,k4 ,! ph5olph?alen is color$ by ! increas$ conc5tration ( ! hydroxide-ion & %[s ! direction ( ! *ange4#cdd ,precipitation by a ,weak ,base 9 ! ,pres5ce ( its ,salts4--,magnesium1 9 contra/ to ! o!r alkal9e e>? metals1 =ms v few difficultly soluble comp\nds4 ,magnesium-ammonium phosphate1 ,mg7,,nh#d7,,po#d1 a d\ble salt1 is ! mo/ *>act]i/ic precipitate = id5tify+ x4 ,magnesium hydroxide1 z ! table ( solubilities %[s1 is also v difficultly soluble4 ,x is readily precipitat$ by potassium or sodium hydroxide1 b ammonium hydroxide1 at be/1 precipitates x only incompletely#cde f solutions ( its salts1 & v commonly does n precipitate x at all--namely1 :5 ammonium salts 9 suffici5t quantity are pres5t 7exp474 ,?is peculi> behavior ( ammonium salts1 9 int]f]+ ) ! precipitation ( magnesium hydroxide1 puzzl$ *emi/s = _m ye>s1 & a numb] ( !ories 7 (f]$ 9 explanation ( x4 ,b !y all prov$ unt5able1 & ! fir/ adequate explanation1 ! "o 9 accord ) all ! facts1 0 only f\nd aft] ! developm5t ( ! !ory ( ionization4 ,its quantitative application to ! case 9 "q gives a p]fect insight into ! relations1 & br+s important confirmation ( ! correctness ( its fundam5tal assumptions4#cdf ,! fact t ammonium salts prev5t ! precipitation ( magnesium hydroxide 0 =m]ly expla9$ z be+ due to ! =mation ( d\ble salts1 su* z ,mg,cl#b1,,nh#d;,cl4 ,x is true t su* d\ble salts exi/1 b1 if _! =mation %\ld prev5t ! precipitation ( magnesium hydroxide1 possibly by includ+ ! magnesium z "p ( a negative ion or radical1#cdg ,mg,cl#c1 !n ! correspond+ d\ble salts ( magnesium *loride ) potassium & sodium *loride 7e4g4 ,mg,cl#b1,k,cl71 :i* are j z /able z ! ammonium salts1 %\ld %[ ! same behavior2 b1 z a matt] ( fact1 ! addition ( potassium *loride does n int]f]e ) ! precipitation ( ! hydroxide by ei!r p#afi potassium hydroxide or ammonium hydroxide 7exp474 ,s ! explanation is unt5able4 ,obvi\sly1 a specific int]f]5ce ( ammonium salts ) ! precipitat+ p[] ( ammonium hydroxide is involv$4 ,b t is exactly :at ! law ( *emical equilibrium1 appli$ to ! ionization ( ammonium hydroxide1 w\ld dem&3 ,z a weak base1 :i* is little ioniz$ 9 pure aque\s solutions1 x is v mu* weak] z a base1 produces a f> small] conc5tration ( ! hydroxide-ion1 :5 readily ionizable salts ( ammonium are add$ to ! solution1#cdh & ! precipitation ( magnesium hydroxide1 & ( metal hydroxides 9 g5]al1 dep5ds on ! conc5tration ( ! hydroxide-ion1 :i* is a factor 9 ! solubility-products ( bases4 ,! precipitation ( magnesium hydroxide1 9 p>ticul>1 dep5ds on ! relation ( ! product ,mg#b ,,ho#b to ! solubility-product con/ant ( magnesium hydroxide4 ,= ! saturat$ aque\s solution1 ! product ,mg#b ,,ho#b is equal to ! solubility-product con/ant1 & f ! solubility ( magnesium hydroxide 7see ! table7 ! value ( ! con/ant is f\nd to be #ae;,e#ab at #ah4 ,! conc5tration ( magnesium-ion is #j4jjj1aed 9 ?is solution4 ,9 a #j4a mol> solution ( magnesium sulphate1 :i* is ioniz$ to ! ext5t ( #cg4c1 ! conc5tration ( magnesium-ion is #j4jcgc1 & x w\ld require a conc5tration great] ?an #b;,e#e ( hydroxide-ion to precipitate any magnesium hydroxide4#cdi ,n[1 ! conc5tration ( ! hydroxide-ion1 9 an ammoniacal solution1 c easily be r$uc$ f> bel[ ?is value by ! addition ( ammonium *loride1 nitrate1 sulphate or o!r readily ionizable ammonium salt to ! solution1 & !n magnesium hydroxide w n be precipitat$4 ,9 solutions ( ammonium hydroxide ! conc5tration ( hydroxide ion = #ah is f\nd f ! relation ,,nh#d ,,ho 3 7,,nh#d,,oh ,,nh#c7 #ah;,e#f 7p4 #afa74 7#a7 ,= ammonium hydroxide1 = in/ance 9 #j4b mol> solution1 & 9 ! abs5ce ( any ammonium salt1 ,,ho ,,nh#d #j4jjai4cej ,?is conc5tration ( ! hydroxide-ion %\ld be m ?an suffici5t to precipitate magnesium hydroxide 9 a #j4a mol> solution ( ! sulphate4#cea ,,exp4 #ajj c4c4 ( a mixture :i* %\ld conta9 magnesium sulphate 9 #j4a mol> solution w\ld require #bdf _/ 7#aj #aj7 or #b4df grams ( ,mg,s,o#d1 #g ,h#b,o4 p#agj ,?is weight ( ! salt is dissolv$ 9 #ej c4c4 ( wat] & #ej c4c4 ( #j4d mol> solution ( ammonium hydroxide is add$ to x4 ,magnesium hydroxide is precipitat$4 7,! precipitation is incomplete because ! ammonium sulphate1 =m$ 9 ! reaction1 r$uces ! ionization ( ammonium hydroxide47 7#b7 ,9 ! pres5ce ( #j4be mol> ammonium *loride1 ! *loride be+ dissociat$ to ! ext5t ( #hj1ceb ! conc5tration ( ! hydroxide-ion 9 a #j4b mol> ammonium hydroxide solution is r$uc$ to #ah;,e#f4cec ,accord+ to ! above calculation ?is is too small a conc5tration to precipitate magnesium hydroxide 9 a #j4a mol> solution ( ! sulphate4 ,,exp4 #a4ce grams ammonium *loride 7! weight correspond+ to #ajj c4c4 ( a mixture conta9+ ammonium *loride 9 #j4be mol> solution7 is dissolv$ 9 #ej c4c4 ( #j4d mol> ammonium hydroxide & #b4df grams ( magnesium sulphate1 dissolv$ z be=e 9 #ej c4c4 ( wat]1 is add$ to ! mixture4 ,no precipitate ( magnesium hydroxide is =m$4 ,9 a simil> fa%ion & = ! same reason1 ammonium salts int]f]e m or less ) ! precipitation ( o!r hydroxides1 = in/ance ) ! precipitation ( mangan\s1 nickel\s1 cobalt\s1 f]r\s1 z9c1 cupric & cadmium hydroxides4 ,b ammonium salts d n prev5t ! precipitation ( alum9ium1 *romium & f]ric hydroxides1 :i* are mu* less soluble ?an ! hydroxides j m5tion$1 & z mu* weak] bases1 7,*ap4 ,x7 are also mu* less readily ioniz$4 ,!y are precipitat$ by small] conc5trations ( ! hydroxide-ion ?an are ! hydroxides ( ! fir/ gr\p1 & _! precipitation may be made quantitative4 ,,exp4 ,f]ric hydroxide is readily precipitat$ :5 #b4g grams ( f]ric *loride ,fe,cl#c1 #f ,h#b,o1 ! weight ( ! *loride requir$ to give #ajj c4c4 ( a #j4a mol> solution1 is dissolv$ 9 z little wat] z possible4 ,! solution is add$ to ! mixture ( magnesium sulphate1 ammonium *loride & ammonium hydroxide obta9$ 9 ! previ\s exp]im5t1 9 :i* no magnesium hydroxide 0 precipitat$4 ,,footnotes3 #cbf ,see ,smi?1 ,g5]al ,inorganic ,*emi/ry1 p4 #dad1 ,g5]al ,*emi/ry = ,colleges1 p4 #bgg2 ,rems51 ,inorganic ,*emi/ry 7advanc$ c\rse71 p4 #aeh4 #cbg ,mg#b may also be precipitat$ z a c>bonate ) ! o!r ions ( ! gr\p 7see ,"p ,,iii74 #cbh ,9 ! case ( ammonium nitrate a diff]5t =m ( decomposition1 namely into nitr\s oxide & wat]1 pr$om9ates1 &1 9 ! case ( ammonium nitrite1 decomposition into nitrog5 & wat] takes place s readily1 t ! decomposition ( ! salt takes t direction *iefly4 #cbi ,table1 p4 #ajf4 #ccj ,t4 ,s4 ,moore1 ,j4 ,*em4 ,soc4 7,london71 #ia1 #acgi 7#aijg74 #cca ,f equation 7,i7 we obta9 directly1 by ! application ( a simple ma!matical trans=mation1 t ,,nh#c ,,nh#d,,oh _/ ,,nh#d,,oh k,,nh#c #a k1 &1 !re=e1 ,,nh#d,,oh ,,nh#c ,,nh#d,,oh _/ k4 ,ins]t+ ?is value = ,,nh#d,,oh 9 equation 7,,ii7 & transf]r+ k1 we h ,,nh#d ,,ho _/ 7,,nh#c ,,nh#d,,oh7 kbase _/ k ,k4 #ccb ,wat] ( cry/allization1 f\nd 9 _m ( ! precipitates us$ 9 qualitative analysis1 w1 z a rule1 be indicat$ only 9 ! =mulas us$ 9 ,"p ,,iii1 9 ! /udy ( ! reactions ( ions4 #ccc ,see ,"p ,,iii z to ! me?od ( vaporiz+ magnesium4 #ccd ,cf4 ,f9dlay1 ,z4 phys4 ,*em41 #cd1 #dji 7#aijj74 #cce ,! solubility ( b>ium sulphate at #ah1 accord+ to ! table1 is #j4jjbc _/ #bcc1 or #a;,e#e mole p] lit]1 & ! salt may be consid]$ completely ioniz$ at ?is dilution4 #ccf ,! solubility 7see ! table7 is #j4aad _/ #ahc4f1 or #f4b;,e#d mole p] lit]1 #hd ( :i* is ioniz$ 7accord+ to conductivity det]m9ations1 ,kohlraus* & ,holborn1 loc4 cit41 p4 #bjj74 ,h5ce ,sr#b ,,s#db #j4jjjfb #j4hd #j4jjje4 #ccg ,to e/abli% equilibrium1 prolong$ dige/+ is sometimes requir$4 ,d\ble salts1 solid solutions & me*anical enclosures are liable to int]f]e ) ! complet5ess ( su* sep>ations by fractional precipitation4 ,resolution & reprecipitation w !n usually effect a suffici5tly accurate sep>ation = mo/ purposes4 ,on acc\nt ( ! possibility ( su* complications1 ! conditions = a successful sep>ation1 )9 limits su* z ^? describ$ 9 ! text1 mu/ 9 all cases be inve/igat$4 #cch ,see ! table at ! end ( ,"p ,,iv4 #cci ,! salt may be consid]$ completely ioniz$ at ?is dilution4 ,ea* molecule ( silv] *romate =ms two silv] ions :5 x is ioniz$4 ,see p4 #ada 9 reg>d to ! =m ! solubility-product takes 9 ! case ( a salt ( ?is type4 #cdj ,! complication1 result+ f ! hydrolysis ( ! *romate1 is n includ$ 9 ?is calculation4 #cda ,cf4 ,f9dlay1 loc4 cit4 #cdb ,ev5 ,guldb]g & ,waage consid]$ ! active mass to be ! fundam5tal factor & simply consid]$ ! total conc5trations to be proportional to ! active masses1 s9ce !y _h no means ( det]m9+ ! proportion ( active sub/ances 9 ! total conc5trations4 #cdc ,see ,n]n/1 ,!oretical ,*emi/ry1 p4 #ecc1 = a full] discussion ( ! relations betwe5 ! new & ! old views on ?is subject4 #cdd ,dietri* & ,whl]1 ,z4 anorg4 ,*em41 #cd1 #aid 7#aijc74 #cde ,on acc\nt ( ! =mation ( an ammonium salt 9 ! reaction4 #cdf ,lov51 ,z4 ,anorg4 ,*em41 #aa1 #djd 7#ahif72 ,h]z & ,muks1 ibid41 #ch1 #ach 7#aijd74 #cdg ,9 t case ! salts w\ld be call$ complex salts1 salts ( a complex ion1 ,mg,cl#c4 ,see ,*apt] ,,xii4 ,!y are really d\ble salts2 cf4 ,smi?1 ,g5]al ,inorganic ,*emi/ry1 p4 #ecf4 #cdh ,see p4 #aad1 & recall ! laboratory exp]im5ts 7,lab4 ,manual1 p4 #i1 #f71 :i* may be giv5 z lecture exp]im5ts at ?is po9t4 #cdi ,call+ x ! conc5tration ( ! hydroxide-ion1 requir$ to saturate a #j4a mol> magnesium sulphate solution ) magnesium hydroxide1 we h #j4jcgc x#b #ae;,e#ab & x #b;,e#e4 #cej ,putt+ ,,ho ,,nh#d y1 we h y#b 3 7#j4b y7 #ah;,e#f4 ,!n y #j4jjai4 #cea #j4jcgc #j4jjaib #j4ac;,e#f1 :i* is consid]ably l>g] ?an ! solubility-product con/ant = magnesium hydroxide1 #ae;,e#ab4 #ceb ,kohlraus* & ,holborn1 p4 #aei4 ,m9or *anges 9 ! degrees ( ionization ( ,mg,s,o#d & ,,nh#d;,cl 7& consequ5tly ( ,,nh#d,,oh7 occur1 :5 ! salts are pres5t toge!r4 ,9 a rigor\s treatm5t1 ! ionization ( ea* salt 9 ! mixture w\ld be calculat$ ) ! aid ( ,arrh5ius's pr9ciple ( isohydric solutions4 #cec ,vide ! analog\s calculation on p4 #aac4 p#aga ,,*apt] ,x ,,alum9ium2 ,,amphot]ic ,,hydroxides2 ,,hydrolysis ,,( ,,salts4 ,,! ,,alum9ium ,,& ,,z9c ,,gr\ps ,! *emi/ry ( ! analytical reactions ( ! alkalies & alkal9e e>?s is extremely simple1--x is ess5tially ! *emi/ry ( well-def9$ bases & _! salts1--& ! sep>ations & id5tifications1 z we h se51 dep5d almo/ entirely on physical diff]5ces r ?an on *emical contra/s4 ,9 ! alum9ium & z9c gr\ps1 :i* are precipitat$ toge!r & :i* w be discuss$ toge!r1 ! *emi/ry ( ! reactions becomes v mu* m complex4 ,!re=e1 we %all n1 z yet1 consid] ! gr\ps z a :ole1 b %all fir/ discuss ! important analytical reactions ( "s comp\nds ( alum9ium4 ,alum9ium ,hydroxide an ,amphot]ic ,hydroxide4--,:]eas ! hydroxides ( ! alkali & alkal9e e>? metals are bases1 pure & simple1 alum9ium hydroxide %[s ! prop]ties bo? ( a base & ( an acid2 x is an amphot]ic hydroxide1 ! t]m amphot]ic indicat+ ! comb9ation ( acid ) basic prop]ties 9 any comp\nd4 ,alum9ium hydroxide dissolves 9 acids4 ,f its solution 9 hydro*loric acid1 an alum9ium salt1 alum9ium *loride ,al,cl#c1 #f ,h#b,o1 is obta9$4 ,x also comb9es ) /rong bases1 dissolv+ = in/ance 9 a solution ( sodium hydroxide & =m+ an alum9ate1 ,na,al,o#b4 ,! two salts m5tion$ are typical repres5tatives ( ! two s]ies ( salts1 :i* alum9ium hydroxide is capable ( =m+4 ,?is dual "* ( ! hydroxide raises a numb] ( int]e/+ que/ions1 :i* "o meets ) q frequ5tly 9 ! /udy ( analytical reactions4 ,"o may ask1 fir/1 h[ alum9ium hydroxide c ionize bo? z an acid & z a base2 second1 :e!r any reason c be giv51 :y x %\ld %[ ! dual nature2 & ?ird1 if x is bo? base & acid1 :y x does n neutralize itself4 ,accord+ to ! be/ k we h on ! subject1 ! molecule ( alum9ium hydroxide has ! foll[+ /ructure or arrangem5t ( its atoms3 ,al7--,o--,h7#c4 ,x is readily se5 t ! cleavage ( ! molecules may produce1 p#agb ei!r alum9ium & hydroxide ions1 *>act]i/ic ions ( a base1 or alum9ate#ced & hydrog5 ions1 *>act]i/ic ions ( an acid3 ,al#c #c ,,oh ,al7--#j--;,h7#c ,al,o#b ,h ,h#b,o4 ,! ionization ( ! hydroxide bo? z an acid & z a base is1 ?us1 q possible on ! basis ( ! molecul> /ructure assign$ to x4 ,9 fact1 all ( ! s-call$ oxyg5 acids are consid]$ to be hydroxides--we h sulphuric acid1 ,o#b,s7,,oh7#b1 phosphoric acid1 ,,op7,,oh7#c1 etc41--exactly z ! bases1 ,mg7,,oh7#b1 etc41 are hydroxides4 ,t br+s u to ! second "q1 :y alum9ium hydroxide %\ld %[ ?is dual "*1 :]eas1 = in/ance1 sodium & magnesium hydroxides1 :i* h simil> /ructures1 d n %[ x4 ,! be/ answ] to ?is "q is f\nd :5 we consid] ! prop]ties ( ! elem5ts & _! d]ivatives 9 connection ) _! position 9 ! p]iodic or natural sy/em ( elem5ts1 :i* %[s ! prop]ties z 7p]iodic7 functions ( ! atomic weights4 ,9 ! second s]ies ( ! elem5ts1#cee omitt+ ! z]o gr\p elem5t neon & tak+ ! elem5ts 9 ! ord] ( increas+ atomic weights1 we h sodium 7#bc71 magnesium 7#bd71 alum9ium 7#bg71 silicon 7#bh71 phosphorus 7#ca71 sulphur 7#cb71 & *lor9e 7#ce4e74 ,"o ( ! prop]ties t are %[n to be functions dep5d5t on ! atomic weight1 is ! prop]ty "u discussion1 namely ! t5d5cy ( ! 7highe/7 hydroxides ( ! elem5ts to ionize z bases or acids1 respectively4 ,x is cle> t ! hydroxides ( ! elem5ts ) ! l[e/ atomic weights 9 ! s]ies1 sodium & magnesium1 %[ ! mo/ pron\nc$ t5d5cy to ionize z bases2 ! hydroxides ( ! elem5ts ) ! highe/ atomic weights %[ ! mo/ pron\nc$ t5d5cy to ionize z acids--p]*loric acid1 7,,ho7,cl,o#c1 & sulphuric acid1 7,,ho7#b,,s#b1 belong to ! /ronge/ acids4 ,9 accordance ) ! und]ly+ pr9ciple ( ! p]iodic sy/em1 ! *ange ( p#agc prop]ties1 9 go+ f "o extreme to ! o!r1 is a function ( ! increase 9 atomic weight & is n sudd5 b gradual4 ,& s ! basic function1 ! t5d5cy to produce ! hydroxide-ion1 is f\nd to gr[ weak] z "o goes f sodium to magnesium & !n to alum9ium1 hydroxide2 & ! acid function1 ! t5d5cy to produce ! hydrog5-ion1 gr[s m>k$ly /rong]1 z "o goes f phosphoric to sulphuric & p]*loric acids4 ,x is n surpris+ to f9d ! two functions exi/+ toge!r1 b 9 r weak =m1 9 ! case ( ! int]m$iate hydroxides1 notably 9 alum9ium hydroxide &1 to "s degree1 9 silicic acid1 ! acid "* beg9n+ be=e ! basic function has ceas$4 ,9 accordance ) ?is view1 alum9ium hydroxide is f\nd to be only a weak1 slightly ioniz$ base1 & a v weak1 ev5 less readily ionizable acid4 ,9 ! case ( silicic acid1 :i* is ! next hydroxide "o meets z "o goes t[>d ! acid end ( ! s]ies1 ! conditions are rev]s$4 ,z ! "n indicates1 x is prim>ily an acid1 b x is a v weak "o1 & a critical scrut9y ( its behavior %[s x to h v weak basic functions1 mu* weak] ?an ^? ( alum9ium hydroxide4 ,! "q may1 inde$1 be rais$1 :e!r ei!r ! basic or ! acid prop]ties really die out altoge!r 9 ! hydroxides1 f "o end ( ! s]ies to ! o!r4 ,9 view ( ! small t5d5cy t[>d sudd5 *anges f\nd 9 nature1 "o might suspect traces ( basic "* to be pres]v$ "r ?r\gh ! s]ies to ! /ronge/ acids1 l p]*loric acid4 ,z a matt] ( fact1 lat] 7see ,*apt] ,,xv71 we %all be oblig$ to consid] possible basic functions ( ! /ronge/ oxyg5 acids1 su* z nitric1 p]*loric1 p]manganic acids1 & "o ( _! mo/ important prop]ties1 _! behavior z oxidiz+ ag5ts1 w be f\nd to be probably intimately associat$ ) ?is remnant ( basic ionization4 ,on ! o!r h&1 fus$ sodium hydroxide w dissolve sodium ) evolution ( hydrog51 sodium oxide1 ,na--,o--,na1 be+ =m$2 & x c readily be %[n1#cef t 9 ! fus$ hydroxide !re mu/ be at lea/ a few ions ,na,o1 besides ,,ho1 ,h1 ,o#b1 & ,na4 p#agd ,! position ( alum9ium 9 ! p]iodic sy/em adequately acc\nts1 !n1 = ! amphot]ic "* ( its hydroxide4#ceg ,common ,occurr5ce ( ,amphot]ic ,hydroxides4--,if we consid] ! "q ( amphot]ic behavior a little long]--its consequ5ces are us$ ext5sively 9 analytical "w--we f9d1 9 ! p]iodic sy/em1 two o!r regul> *anges conc]n+ acid & basic functions1 only "o ( :i* we %all discuss "h4#ceh ,:ile 9 a s]ies ( elem5ts ! acid "* ( ! hydroxides increases ) ! atomic weight1 9 a family ( elem5ts ! rev]se relation holds4 ,f nitrog5 to bismu?1 9 ! nitrog5 family ( ! six? column ( ! p]iodic sy/em1 ! acid "* ( ! hydroxides gr[s /eadily weak]1 ! basic "* increases1 & we f9d1 aga91 t ! int]m$iate elem5ts1 notably ars5ic & antimony1 produce hydroxides1 :i* %[ m>k$ly amphot]ic "*4 ,if1 9 ! second s]ies ( ! p]iodic gr\p1 "o goes back f alum9ium to magnesium hydroxide1 9 accordance ) ! fir/ g5]al pr9ciple laid d[n a mu* /rong] base is f\nd2 & if "o !n goes1 9 ! magnesium family1 to ! hydroxide ( ! elem5t ( next l[] atomic weight1 gluc9um or b]yllium1 "o aga9 meets1 9 accordance ) ! second pr9ciple laid d[n1 a weak] basic & m acidic hydroxide ?an magnesium hydroxide2 9 o!r words1 ! basic & acid functions rev]t closely to ^? exhibit$ by alum9ium hydroxide4 ,gluc9um hydroxide is a pron\nc$ amphot]ic hydroxide & resembles alum9ium hydroxide s closely t1 9 ! e>ly hi/ory ( *emi/ry1 x 0 mi/ak5 = ! latt]4 ,if "o goes f gluc9um back to li?ium1 9 ! same s]ies ( ! p]iodic sy/em1 & f li?ium to ! elem5t ) ! next l[] atomic weight 9 ! same gr\p1 "o comes to hydrog51 :i* =ms "o ( ! mo/ important & int]e/+ ( ! p#age amphot]ic hydroxides1 wat]4 ,! ionization ( wat]1 slight z x is1 yields hydrog5-ion & hydroxide-ion1 ! ions *>act]i/ic ( acids & ( bases1 & wat] is plac$ among ! weake/ ( ! acids 7see table1 p4 #ajd7 z well z among ! weake/ ( ! bases 7table1 p4 #ajf74 ,we %all return to ^! relations1 pres5tly1 & %all f9d t ! app>5t weakness ( wat]1 z a base & z an acid1 is seem+ly v l>gely due to ! fact t wat] repres5ts only an extremely dilute solution 7see p4 #ff7 ( ! real hydroxide1 ,,hoh1 or hydrol1 & consi/s v l>gely ( a comp\nd 7,h#b,o7#b4 ,h#b,o1 or hydrol1 is1 p]haps1 n v mu* weak] z an acid or z a base1 ?an is alum9ium hydroxide4 ,l[] oxides ( elem5ts 9 ! high] 7acid-=m+7 gr\ps %[ a less pron\nc$ acid-=m+ "* ?an ! high] oxides1 & a great] t5d5cy to produce bases z well z acids1 & are (t5 amphot]ic4 ,*romium hydroxide is ( ?is type4 ,9 view ( all ^! facts1 & 9 view1 also1 ( ! fact t ! majority ( ! sev5ty-odd elem5ts _c lie at ! ends ( ! p]iodic sy/em b are f\nd 9 ! middle1 x is n surpris+ to f9d t pron\nc$ amphot]ism is %[n by a l>ge numb] ( metal hydroxides2 x is1 p]haps1 ! rule r ?an ! exception4 ,a consid]able numb] ( ! elem5ts 9 ! middle ( ! sy/em are r>e elem5ts & t is p]haps ! *ief reason :y ?is relation does n /& out m prom95tly 9 ! consid]ation ( ! common acids & bases4 ,amphot]ic ,"* ( ,hydroxides ,consid]$ 9 ,analysis4--,! amphot]ic "* ( hydroxides is frequ5tly made use ( 9 analytical "w 9 ! sep>ation & id5tification ( v>i\s elem5ts &1 :5 pres5t1 x mu/ always be consid]$1 9 ord] to escape possible error4 ,! foll[+ hydroxides ( ! common elem5ts %[ pron\nc$ amphot]ic "*3 alum9ium1 *romic1 z9c1 lead1 /ann\s1 antimon\s hydroxides & ars5i\s1 plat9ic1 auric1 antimonic & /annic acids4 ,ars5ic acid1 f]ric hydroxide & silicic acid %[ exce$+ly slight1 b p]ceptible1 amphot]ic "*1 suffici5t to affect1 to a c]ta9 degree1 _! analytical behavior4#cei p#agf ,self-,neutralization ( ,amphot]ic ,sub/ances4#cfj--,we may turn n[ to ! ?ird "q rais$ 9 connection ) alum9ium hydroxide1 to ! inquiry 7p4 #aga71 :y alum9ium hydroxide1 ! acid1 does n neutralize alum9ium hydroxide1 ! base4 ,9 fact1 ! base mu/ & does =m a salt ) ! acid4 ,b ! salt is =m$ only to a m9imal ext5t1 z ! result ( ! fact t ! base is a v weak base1 ! acid an exce$+ly weak acid4 ,su* exce$+ly weak bases & acids %[ little t5d5cy to comb9e ) ea* o!r to =m salts 9 ! pres5ce ( wat]1 especially if "o or bo? are difficultly soluble 9 wat]1 z 9 ! pres5t in/ance4 ,! behavior ( alum9ium hydroxide1 9 ?is respect1 is "p ( a mu* l>g] & m g5]al "q1 gr[+ out ( ! fact t wat] is a v weak acid & base1 z has be5 se51 &1 to a great] or less] ext5t1 reacts z su* ) salts1 :i* are dissolv$ 9 x4 ,?is action ( wat] plays an important rle 9 _m analytical reactions1 & especially1 also1 9 ! reactions ( alum9ium salts4 ,we %all1 fir/1 discuss ?is l>g] "q ( ! action ( wat]1 z an ionog51 on salts1 & !n return 7p4 #ahg7 to ! problem ( ! self-neutralization ( an amphot]ic hydroxide4 ,,hydrolysis ,,( ,,salts ,ionization ( ,wat]4--,we may fir/ consid]1 v briefly1 ! evid5ce t wat] is ioniz$ ev5 to ! ext5t indicat$ by ! ionization con/ants giv5 9 our tables4 ,x may be said t ! pure/ wat] ev] prep>$#cfa %[s a m9imal conductivity1 f :i* ! conc5trations ( its hydrog5 & hydroxide ions & ! value ( ! ionization con/ant may be calculat$4 ,= ! ionization ( wat] we h ,h ,,ho _/ ,nonioniz$ wat] ,k,ion4 ,z ! conc5tration ( pure wat]1 or ( ! wat] 9 dilute solutions1 may be consid]$ ne>ly a con/ant1 we may put ,h ,,ho ,k,h#b,o4 ,?is is ! relation mo/ commonly1 & mo/ conv5i5tly1 us$4 ,x is free f all assumptions z to ! molecul> weight ( ! nonioniz$ wat]1 ! calculation ( ! conc5trations p#agg ,h & ,,oh be+ indep5d5t ( any su* assumption4 ,! value ( ,k,h#b,o increases decid$ly ) an increase 9 ! temp]ature1#cfb :]eas ! ionization con/ant ( an ord9>y acid1 su* z acetic acid1 is affect$ v little by *anges 9 temp]ature4 ,?is peculi> increase ( ! ionization ( wat] at high] temp]atures is und\bt$ly due to ! increas+ dissociation ( ! complex wat] molecules into hydrol molecules 7see p4 #ff71 :i*1 presumably1 are mo/ easily ioniz$4 ,n[1 ! value ( ! con/ant ,k,h#b,o1 at any temp]ature1 may be det]m9$ 9 "s half a doz5 diff]5t & indep5d5t ways1 includ+ ! conductivity me?od m5tion$1 & "o ( ! mo/ rem>kable developm5ts ( ! !ory ( ionization is t all ( ^! me?ods lead to concordant results4#cfc ,aside f consid]ations bas$ on its ionization1 wat] may be %[n1 by its *emical behavior1 to h ! functions ( an acid & ( a base1 & ! conclusions rea*$ are 9 complete accord ) ^? rea*$ ) ! aid ( ! !ory ( ionization4 ,wat] is ,an ,acid4--,if ! oxide ( a metal su* z copp]1 lead or calcium1 is treat$ ) an acid1 a salt is =m$ by ! comb9ation ( ! two2 = in/ance1 we h ,pb,o ,h,cl ,pb7,,oh7,cl1 ,pb7,,oh7,cl ,h,cl ,pb,cl#b ,h#b,o1 ,pb,o #b ,h,cl ,pb,cl#b ,h#b,o1 ,ca,o #b ,h,cl ,ca,cl#b ,h#b,o4 ,wat] w comb9e ) a numb] ( oxides v mu* 9 ! same mann] & sometimes ) su* vigor1 t consid]able heat is evolv$1 z 9 ! slak+ ( lime 7exp473 ,ca,o ,,hoh ,ca7,,oh7#b4 ,wat] 9 ?is1 & simil> actions1 takes ! place ( & plays ! rle (1 an acid1 & ! metal hydroxides or bases appe> z its salts4#cfd ,x is a v weak acid1 :i* c easily be driv5 out ( its salts by any /rong] acid 7neutralization ( bases71 b t does n alt] ! conclusions rea*$4 ,consid]$ f ! po9t ( view ( ! !ory ( ionization1 ! relation p#agh w\ld be express$ by say+ t 9 ! common bases ! positive hydrog5 ion ( wat] has be5 replac$ by "s o!r positive or metal ion4 ,! salt ( any acid c\ld be def9$ 9 exactly ! same way4 ,wat] z a ,base4--,acid oxides1 su* z c>bon dioxide1 silicon dioxide1 ars5i\s oxide1 comb9e m or less readily ) bases1 su* z sodium hydroxide1 to =m salts3 ,,co#b ,na,o,h ,na,h,c,o#c1 ,z#b,o#c #b ,na,o,h #b ,na,as,o#b ,h#b,o4 ,a numb] ( acid oxides comb9e ) wat] 9 exactly ! same mann]1 & sometimes ) su* trem5d\s vigor1 t great c>e mu/ be tak5 9 br++ ! two toge!r1 z is ! case :5 sulphur trioxide or phosphorus p5toxide are add$ to wat] 7,exp474 ,we h ,p#b,o#e ,,hoh #b ,,hpo#c4 ,x is evid5t t 9 su* actions wat] may take ! place (1 & play ! rle (1 an ord9>y base1 =m+ ! acids1 :i* may well be def9$ z hydrog5 salts4#cfe ,x is true t ! basic prop]ties ( wat] are s weak1 t ! metal ion ( ev5 a weak base1 l ammonium hydroxide1 w replace ! hydrog5-ion 9 its salts1 ! acids1 q readily 7,h,cl ,,nh#d,,oh ,,nh#d;,cl ,h#b,o74 ,b su* a weak base1 9 turn1 w h to give way1 ( c\rse1 to /ill /rong] bases2 = in/ances1 ,,nh#d;,cl ,na,o,h ,na,cl ,,nh#d,,oh4 ,f ! po9t ( view ( ! !ory ( ionization1 ! hydrog5-ion is positive1 l all ! o!r metals ions ^: hydroxides are bases4 ,!re %\ld be no difficulty1 !re=e1 9 consid]+ wat] to h ! *emical prop]ties ( a base z well z ( an acid4 ,its *emical activities z su*1 weak z !y may be1 mu/ be satisfi$ :5ev] x is pres5t4 ,^! activities lead to ! hydrolysis or ! decomposition ( salts by wat]1 9 great] or less] degree1 :5ev] wat] is us$ z a solv5t = salts4 ,action ( ,wat] on a ,salt ( a ,/rong ,base & a ,/rong ,acid4--,if sodium *loride1 a typical salt =m$ f a /rong base & a /rong acid1 is dissolv$ 9 wat]1 x is ioniz$ to a consid]able ext5t4 ,consid]+ ! solution f a me*anical po9t ( view1 we w\ld expect t ! sodium ions1 mov+ 9 all directions1 w\ld collide occasionally ) hydroxide ions1 :i* are =m$ f ! wat] & are pres5t 9 m9ute b def9ite quantity4 ,"s ( ! collisions mu/ result 9 ! =mation ( sodium hydroxide1 z we h no reason to suppose t ! result w\ld diff] f t 9 o!r cases :]e positively *>g$ p>ticles meet ) negatively *>g$ ones4 ,h[ev]1 s9ce sodium hydroxide is an ionog51 ) a v great t5d5cy to ionize1 & s9ce !re is pres5t only a m9ute conc5tration ( ! hydroxide-ion1 ! p#agi equilibrium conditions w be satisfi$ :5 only traces ( ! nonioniz$ hydroxide are =m$4 ,9 a simil> mann]1 we mu/ expect to h traces1 & only traces1 ( nondissociat$ hydro*loric acid =m$ by ! union ( *loride ions ) "s ( ! hydrog5 ions ( ! wat]4 ,s9ce hydrog5 *loride & sodium hydroxide %[ practically ! same t5d5cy to ionize 7tables1 pp4 #ajd & #ajf71 ! two k9ds ( ions :i* wat] =ms1 ! hydrog5-ion & ! hydroxide-ion1 w be us$ up to a v slight & practically equal ext5t to =m nonioniz$ sodium hydroxide & hydrog5 *loride1 b ! ions w be imm$iately reg5]at$1 & 9 equal conc5trations1 f ! nonioniz$ wat] :i* is pres5t4 ,all ! equilibrium requirem5ts w be satisfi$ :5 traces ( sodium *loride h be5 conv]t$ into nonioniz$ sodium hydroxide & hydrog5 *loride4 ,su* a solution1 conta9+ no excess ( ! hydrog5- or ! hydroxide-ion1 w\ld react neutral4 ,! action may be express$ by ! equation#cff ,na,cl ,na ,cl ,h#b,o ,,ho ,h ,na ,,ho ,na,o,h ,cl ,h ,h,cl4 ,! decomposition ( sodium *loride by wat]1 :i* "o may pr$ict on ! basis ( ^! !oretical consid]ations1 may be demon/rat$1 slight z x is1 by ! foll[+ exp]im5t4#cfg ,,exp4 ,a p9* ( sodium *loride is br\ght into a plat9um crucible1 :i* is previ\sly heat$ 9 a bla/ lamp to a bright yell[ heat 7#aajj72 !n #a c4c4 ( wat] is introduc$1 drop by drop4 ,a /eam cu%ion is =m$ at once 7,leid5fro/'s ph5om5on74 ,aft] ab\t half ( ! wat] has be5 evaporat$ 7half a m9ute71 ! wat] is p\r$ into a solution color$ ) blue litmus2 x is *ang$ to r$ by an excess ( hydro*loric acid 9 ! wat]4 ,! crucible is cool$1 & ! salt rema9+ 9 x is dissolv$ 9 a little wat] & ! solution p\r$ into a r$ litmus solution2 ! latt] turns blue4 ,! sodium *loride has obvi\sly be5 p>tially decompos$1 by ! wat]1 into its base & its acid2 ! decomposition is favor$ by ! high temp]ature & by ! fact t ! hydrog5 *loride p#ahj =m$ c pass ?r\gh ! /eam cu%ion into ! wat]1 :ile ! sodium hydroxide is left beh9d4 ,! removal ( a product ( ! decomposition w\ld favor its progress 7see4 p4 #aad74 ,! conclusions conc]n+ salts ( ! type ( sodium *loride may !n be summ>iz$ 9 ! /atem5t1 t salts =m$ by ! union ( a v /rong base ) an equally /rong acid are only v slightly decompos$ by wat] & _! solutions %[ a neutral reaction4 ,! decomposition ( a salt by wat] into its compon5t base & acid is call$ hydrolysis & ! salt is said to be hydrolyz$ 9 ! action4 ,action ( ,wat] on ! ,salt ( a ,/rong ,base ) a ,weak ,acid4--,! relations are simil> 9 pr9ciple1 b q diff]5t 9 degree & 9 net result1 :5 ! salt ( a v /rong base1 comb9$ ) a weak acid1 is dissolv$ 9 wat]4 ,potassium cyanide is a typical salt ( ?is k9d1 & ! /udy ( its hydrolysis w illu/rate ! behavior ( ?is class ( salts4 ,! hydrolysis takes place accord+ to ! equations ,,kcn ,k ,,cn ,,hoh ,,ho ,h ,k ,,ho ,,koh ,,cn ,h ,,hcn4 ,:5 ! cyanide is dissolv$ 9 wat]1 we mu/ obta91 = ! same reasons z 7 develop$ 9 ! discussion ( ! hydrolysis ( sodium *loride1 a little nonioniz$ potassium hydroxide1 f ! union ( potassium ions ) hydroxide ions1 =m$ by ! wat]4 ,potassium hydroxide be+ a /rong1 easily ionizable base1 !re w be only a slight t5d5cy t[>ds ?is union4 ,hydrocyanic acid1 on ! o!r h&1 is an exce$+ly weak acid4 ,! value ( its ionization con/ant ,k,,hcn ,h ,,cn _/ ,,hcn is only #g;,e#aj1 z comp>$ ) a simil> ratio approximat+ #a = potassium hydroxide 7,k ,,ho _/ ,,koh #a2 see ! tables1 p4 #ajd & p4 #ajf & see pp4 #ajf-g74 ,! hydrog5-ion1 =m$ f ! wat]1 mu/ !re=e comb9e ) cyanide-ion1 to =m nonioniz$ hydrocyanic acid1 mu* m completely ?an ! hydroxide-ion comb9es ) potassium-ion4 ,) ! disappe>ance ( ! ions ( wat]1 9 ?is case notably ( its hydrog5 ions1 m wat] mu/ ionize to satisfy ! ionization con/ant p#aha = wat] 7p4 #agf71 & ! =mation ( hydrocyanic acid w cont9ue1 t[>ds ! satisfy+ ( its own con/ant4 ,x is important to note t1 = ! reasons giv51 ! hydrog5-ion ( wat] is us$ up to a f> great] ext5t ?an is ! hydroxide-ion2 ! latt] !re=e accumulates1 & ?is accumulation results 9 ! =mation ( small] & small] conc5trations ( ! hydrog5-ion1 by ! wat]4 ,s9ce ,h ,,ho #a4b;,e#ad 7at #be2 p4 #ajd71 z ,,ho gr[s l>g]1 ,h mu/ gr[ proportionally small]4 ,! suppression ( ! hydrog5-ion by ! accumulation ( ! hydroxide ion w1 ultimately1 make ,h s small1 t ! equilibrium ratio ,h ,,cn _/ ,,hcn w equal ! equilibrium con/ant4 ,s9ce ! union ( ! hydrog5-ion ) ! cyanide-ion1 to =m little ioniz$ hydrocyanic acid1 is ! ma9 mov+ cause = ! *anges1 ! latt] w !n come to a /&/ill & equilibrium w be e/abli%$4 ,! net result ( ! action ( wat] on potassium cyanide may be said to consi/ 9 ! =mation ( practically nonioniz$ hydrocyanic acid & ! lib]ation ( 7*iefly7 ioniz$ potassium hydroxide1 until all ! equilibrium con/ants ( ! sy/em are satisfi$4 ,we note t potassium cyanide solution mu/ react /rongly alkal9e 7exp47 & t a free acid 7e4g4 ,,hcn7 may well exi/ 9 ! pres5ce ( a free base 7e4g4 ,,koh71 provid$ ! acid is pres5t 9 a nonioniz$1 & !re=e *emically inactive1 condition 7inactive z an acid74 ,ignor+ ! 7practically7 unimportant =mation ( small quantities ( nonioniz$ potassium hydroxide1 we may summ>ize ! action 9 a s+le equation1 :i* %[s ! ma9 action3 ,,cn ,,hoh ,,hcn ,,ho4 ,:]eas wat]1 z an acid & z a base1 is s exce$+ly weak1 t x c =m b traces ( its own salts1 sodium hydroxide & hydro*loric acid1 :5 act+ on sodium *loride & compet+ = ! base ) su* a /rong acid z hydro*loric acid & = ! acid ) su* a /rong base z sodium hydroxide 7see p4 #agi71 ! result1 evid5tly1 is q diff]5t :5 wat] competes = a base ) s weak an acid z hydrocyanic acid4 ,9 ?is case1 we note t a consid]able quantity ( 7ioniz$7 potassium hydroxide1 ! salt ( wat] 9 its rle ( an acid1 is =m$ z a result ( ! action ( wat] on potassium cyanide4 p#ahb ,! !ory ( ionization1 ) ! aid ( ! law ( *emical equilibrium1 gives u ! means = accurately def9+ ! relative conc5trations ( ! products1 9 ! f9al condition ( equilibrium4#cfh ,= ! weak acid1 hydrocyanic acid1 we h ! condition ( equilibrium ,h ,,cn _/ ,,hcn ,k,,hcn #g;,e#aj4 ,! symbols ,h1 ,,cn & ,,hcn d5ote ! f9al conc5trations = ! condition ( equilibrium1 indicat$ 9 ! equations on p4 #ahj2 9 su* a mixture ,h is n equal to ,,cn1 z x is 9 pure solutions ( hydrocyanic acid 9 wat]4 ,,cn1 repres5t+ ! total conc5tration ( ! cyanide-ion1 is v mu* l>g] ?an ,h1 s9ce ! salt1 potassium cyanide1 produces ! cyanide-ion 9 l>ge conc5trations4 ,= wat]1 we h ,h ,,ho ,k,,hoh #a4b;,e#ad1 at #be4 ,"h1 aga91 ! symbols repres5t ! f9al1 total conc5trations ( ! ions 9 ! mixture & ,,ho is mu* l>g] ?an ,h1 s9ce hydroxide-ion is =m$ 9 l>ge quantities1 z describ$ above4 ,comb9+ ! two equations1 we h3 ,,cn _/ 7,,hcn ,,ho7 ,k,,hcn _/ ,k,,hoh ,k,hydrolysis4 ,! cyanide-ion1 ^: conc5tration is express$ by ,,cn1 is =m$ practically altoge!r by ! ionization ( potassium cyanide1 :i* is an easily ionizable & almo/ entirely ioniz$ salt2 ! hydroxide-ion1 ^: conc5tration is express$ by ,,ho1 is =m$ by ! ionization ( potassium hydroxide1 :i* is an easily ionizable base1 ioniz$ to practically ! same degree z is ! potassium cyanide 9 ! solution4 ,if we repres5t ! total conc5tration ( ! potassium cyanide1 ioniz$ & nonioniz$1 at ! po9t ( equilibrium1 by ,,kcn & its degree ( ionization by #a1 & if we repres5t1 simil>ly1 ! total conc5tration ( potassium hydroxide by ,,koh & its degree ( ionization by #b1 ! equilibrium equation may be writt53 #a,,kcn _/ 7,,hcn #b,,koh7 ,k,,hcn _/ ,k,,hoh ,k,hydrolysis4 ,s9ce ! degrees ( ionization ( ! two /rong electrolytes are practically ! same1 we h fur!r simply ,,kcn _/ 7,,hcn ,,koh7 ,k,,hcn _/ ,k,,hoh ,k,hydrolysis4 ,! ma!matical equations give u a measure ( ! ext5t to :i* wat] mu/ decompose or hydrolyze ! salt 9 "q1 z express$ 9 ! *emical equations 7p4 #ahj74 ,! ext5t ( ! hydrolysis1 cle>ly1 dep5ds on ! relative ionization con/ants ( hydrocyanic acid & wat]1 ! two acids compet+ = ! base4 ,f ! kn[n values ( ! con/ants1 "o may calculate t1 at #be1 9 a solution ( #f4e grams potassium cyanide 9 a lit] 7#j4a mol>71 almo/ #a4c ( ! cyanide is decompos$ into potassium hydroxide & hydrocyanic acid4 ,s9ce e molecule ( hydrolyz$ salt =ms "o molecule ( p#ahc ! hydroxide & "o molecule ( ! acid1 we may put ,,koh ,,hcn x & ,,kcn #j4a x4 ,! ionization con/ant1 ,k,,hcn #g;,e#aj1 & ,k,,hoh #a4b;,e#ad1 at #be4 ,ins]t+ ^! values into ! equation ,,kcn _/ 7,,hcn ,,koh7 ,k,,hcn _/ ,k,,hoh we h3 7#j4a x7 _/ x#b #g;,e#aj _/ #a4b;,e#ad4 ,"h x #j4jjac4 ,?is is #a4c ( ! #j4a mole ( cyanide us$4 ,"o may conv9ce himself1 z foll[s1 t ! con/ants are satisfi$ :5 ! decomposition ( ! cyanide has proce$$ to ?is po9t3 ! degrees ( ionization ( ! potassium cyanide & potassium hydroxide1 #a & #b1 may be tak5 z #he 7! same z ! degree ( ionization ( ! simil> electrolyte ,k,cl 9 #j4a mol> solution74 ,!n ,,ho #j4he #j4jjac #j4jjaa2 ,,cn #j4he 7#j4a #j4jjac7 #j4jhc2 ,h #a4b;,e#ad _/ ,,ho #a4a;,e#aa4 ,= ,h ,,cn _/ ,,hcn we h !n3 7#a4a;,e#aa #j4jhc7 _/ 7#j4jjac7 or #g;,e#aj1 ! value = ! ionization con/ant ( hydrocyanic acid4 ,x %\ld be not$ t1 :]eas 9 pure wat] at #be ,h ,,ho 7#a4b;,e#ad7 #a4a;,e#g1 9 ! solution "u consid]ation ,,ho has increas$ to ! value #j4jjaa & ,h is only #a4a;,e#aa4 ,! relation develop$ = ! hydrolysis ( potassium cyanide is a g5]al "o1 hold+ = ! hydrolysis ( salts1 ( ! type ,me,x1 ( a weak acid ) a /rong base4 ,x may be express$ 9 g5]al z foll[s3 = ! hydrolysis ( a salt accord+ to ,me,x ,,hoh ,me,o,h ,,hx1 :]e ,,hx is a weak acid & ,,meoh a /rong base1 we h3#cfi ,salt _/ 7,acid ,base7 ,k,acid _/ ,k,,hoh4 ,x is cle>1 f ! equation1 t ! weak] ! acid ( ! salt 7measur$ by ! ionization con/ant ,k,acid1 ! num]ator on ! "r71 ! m w wat]1 cet]is p>ibus1 be able to drive x out ( its salt & =m its own salt1 ! base 7! small] ! num]ator on ! "r1 ! l>g] mu/ be ! d5om9ator on ! left74 ,! conclusions may be summ>iz$ 9 ! /atem5t t ! salts ( /rong bases ) weak acids are m or less decompos$ by wat] 7hydrolyz$7 & ! result+ solutions mu/ react alkal9e4 ,we f9d1 z a matt] ( fact1 t aque\s solutions ( potassium cyanide1 sodium c>bonate1 sodium sulphide1 borax 7see ! table1 p4 #ajd71 all react /rongly alkal9e to litmus 7exp474 ,conv]sely1 x may be said1 t if ! sodium or potassium salt ( an acid dissolves 9 wat] ) a decid$ly alkal9e reaction1 x is ! salt ( a weak1 poorly ioniz$ acid4#cgj p#ahd ,action ( ,wat] on a ,salt ( a ,/rong ,acid ) a ,weak ,base4--,exactly simil> relations obta9 9 ! case ( salts ( /rong acids ) weak bases3#a !y are decompos$1 to a great] or less ext5t1 into ! free1 /rong1 l>gely ioniz$ acid & ! free1 sc>cely ioniz$ weak base1 ! decomposition be+ /opp$ by ! accumulation ( ! free /rong acid 7m exactly1 ( ! hydrog5-ion74 ,su* solutions react /rongly acid1 z 9 ! case ( ! *loride1 nitrate1 sulphate ( alum9ium1 ( iron 7f]ric71 ( *romium1 & ( simil> salts ( weak bases4 ,= ,me,x ,,hoh ,me,o,h ,,hx1 :]e ,me,o,h is a weak base & ,,hx a /rong acid1 we h z be=e3#cga ,me _/ 7,h ,me,o,h7 ,salt _/ 7,acid ,base7 ,k,base _/ ,k,,hoh4 ,action ( ,wat] on a ,salt ( a ,base & an ,acid1 ,bo? ( :i* are ,weak4--,we w n[ turn to ! consid]ation ( ! action ( wat] on ! f\r? class ( salts1 ! salts ( a weak base ) a weak acid4#cgb ,l all salts1 su* a salt1 say ,me,x1 w\ld ionize v readily1 :5 dissolv$ 9 wat] 7! few exceptions to readily ionizable salts are n "u consid]ation71 &1 9 ?is case1 bo? ! positive & ! negative ions w\ld h to comb9e respectively ) ! hydroxide & ! hydrog5 ions ( wat] to =m ! nonioniz$ weak base & ! nonioniz$ weak acid1 & satisfy two v small con/ants1 ,k,base & ,k,acid3 ,me ,,ho _/ ,me,o,h ,k,base & ,h ,x _/ ,,hx ,k,acid4 ,bo? ! hydrog5 & ! hydroxide ions ( wat] w\ld disappe>1 & 9 approximately equal quantity1 if ! base & acid 7 approximately equally weak1 & ! ions w\ld be reg5]at$ f wat] ) no accumulation ( ei!r "o to suppress ! o!r1 z 9 ! two previ\s cases consid]$4 ,"u ^! circum/ances1 ! decomposition by wat] mu/ proce$ v mu* fur!r ?an 9 ! previ\s cases4 ,= in/ance1 9 ! hydrolysis ( potassium cyanide 9 #j4a mol> solution1 at #be1 we f9d ! conc5tration ( ! hydrog5-ion ,h r$uc$#cgc f #a4a;,e#g1 its p#ahe value 9 pure wat]1 to #a4a;,e#aa1 z a result ( ! accumulation ( potassium hydroxide 7! hydroxide-ion71 & only ?is small value = ,h appe>s 9 ! equation = ! =mation ( ! free acid1 ,,hcn 7fir/ equation1 p4 #ahb2 vide ! calculation1 p4 #ahc74 ,b1 9 ! pres5t case1 ! factors ,,ho & ,h1 9 ! equations on p4 #ahd1 ma9ta9 practically _! orig9al value1 ab\t ! same z 9 pure wat]1 & ! =mation ( nonioniz$ ,me,o,h & ,,hx mu/ g correspond+ly fur!r to satisfy ! con/ants ,k,base & ,k,acid4 ,j h[ f> ! action mu/ proce$1 c be =mulat$ ) ! aid ( ! !ory ( ionization & ! law ( *emical equilibrium1#cgd mu* 9 ! same way z = ! hydrolysis ( potassium cyanide4 ,! f9al equation1 z develop$ by ,arrh5ius1 reads3 ,me ,x _/ 7,,hx ,me,o,h7 #b ,salt#b _/ 7,acid ,base7 7,k,acid ,k,base7 _/ ,k,,hoh ,k1 9 :i* ,k,acid & ,k,base repres5t ! ionization con/ants ( ! acid & ! base1 z giv5 9 ! tables 7pp4 #ajd & #ajf71 & is ! degree ( ionization ( ! salt4 ,= ! cyanide ( a base1 :i* is z weak a base z hydrocyanic acid is an acid1 we f9d t ! decomposition by wat]1 at #be 9 a #j4a mol> solution1 mu/ comprise #ii4cecge ( ! salt1 9 ord] to e/abli% equilibrium4 ,9 ! case ( potassium cyanide1 9 #j4a mol> solution1 only #a4c ( ! salt is decompos$ 7p4 #ahb74 ,n[1 if bo? ! free base & ! free acid are v difficultly soluble1 !n ! conc5trations ,me,o,h & ,,hx1 respectively1 9 ! solution _c g beyond a c]ta9 m9ute limit4 ,9 view1#cgf !n1 ( ! v small value1 ,k,base1 ( ! ratio ,me ,,ho _/ ,me,o,h & ! m9ute value t ! second t]m ,me,o,h has "u ^! conditions1 ! fir/ t]m ,me ,,ho mu/ h a correspond+ly small] value4 ,x is cle>1 !re=e1 t 9 su* a solution nei!r ! nonioniz$ base1 ,me,o,h1 nor its ion1 ,me1 c exi/ 9 m ?an m9ute quantities :5 ! equilibrium con/ants are satisfi$4 ,! same conclusion is rea*$ reg>d+ ! p#ahf possibility ( ! exi/5ce ( ! difficultly soluble acid ,,hx & its ion ,x1 9 m ?an m9imal quantities4 ,s9ce1 !n1 nei!r ! ion ,me nor ! ion ,x c be pres5t 9 m ?an traces1 _! salt1 ,me,x1 :i* is consid]$ readily ionizable1 also _c exi/ 9 aque\s solutions1 except 9 traces4 ,! quantitative relations are evid5t f ! equilibrium equation 7p4 #ahe73 ,me ,x _/ 7,,hx ,me,o,h7 #b ,salt#b _/ 7,acid ,base7 7,k,acid ,k,base7 _/ ,k,,hoh ,k4 ,x is evid5t t ! conc5tration ( ! salt1 ,salt1 :i* is capable ( exi/5ce 9 aque\s solution1 is1 9 ! fir/ place1 ! small] ! small] ! values = ,k,acid & ,k,base are1 i4e4 ! weak] ! acid & ! base are2 &1 9 ! second place1 x is ! small] ! small] ! values = ,acid & ,base are1 :i*1 9 ! pres5t in/ance1 repres5t ! conc5trations ( ! difficultly soluble acid & base 9 saturat$ solution1 i4e4 _! solubilities4 ,we rea* ! conclusion t salts ( v weak bases & v weak acids are v consid]ably decompos$ by wat]1 &1 if bo? ! acid & ! base are difficultly soluble 9 wat]1 ! decomposition is practically complete4 ,conv]sely1 su* a v weak1 difficultly soluble base w n comb9e ) a v weak1 difficultly soluble acid to =m a salt 9 ! pres5ce ( wat]4 ,an in/ance ( ! fir/ k9d is f\nd 9 ! case ( alum9ium sulphide1 ! salt ( a v weak1 difficultly soluble base1 alum9ium hydroxide1 ) a r little soluble1 weak acid1 hydrog5 sulphide 7see table1 p4 #ajd74 ,we f9d t :5 a piece ( alum9ium sulphide1 prep>$ by dry me?ods1 is dropp$ into wat] 7exp471 a precipitate ( alum9ium hydroxide is imm$iately =m$ & evolution ( hydrog5 sulphide occurs4 ,we h ,al#b,s#c #b ,al#c #c ,s#b1 #f ,,hoh #f ,,ho #f ,h #b ,al#c #f ,,ho #b ,al7,,oh7#c #c ,s#b #f ,h #c ,h#b,s 4 ,an in/ance :]e a v weak insoluble acid w n comb9e1 appreciably1 ) a v weak insoluble base1 is f\nd 9 ! case ( alum9ium hydroxide4 ,a developm5t ( ! equilibrium equations = its ionization z a base & its ionization z an acid w\ld %[1 t all ! con/ants w\ld be readily satisfi$1 :5 a v m9ute quantity ( dissolv$ ioniz$ alum9ium alum9ate is =m$4 p#ahg ,self-,neutralization ( ,amphot]ic ,hydroxides4--,we may consid] a saturat$ solution ( alum9ium hydroxide1 9 contact ) ! solid hydroxide4 ,= ! acid ionization1#cgg ,al7,,oh7#c ,al,o#b ,h ,h#b,o1 we h ,al,o#b ,h _/ ,al7,,oh7#c ,k,acid4 ,simil>ly1 = ! basic ionization1#cgh ,al7,,oh7#c 7,al,o7 ,,ho ,h#b,o1 we h ,al,o ,,ho _/ ,al7,,oh7#c ,k,base4 ,! =mation ( traces ( nonioniz$ 7basic7 alum9ium alum9ate w\ld satisfy ! equilibrium requirem5ts = ,al,o ,al,o#b ,al,o7,al,o#b71 s9ce ! alum9ate1 l o!r alum9ates1 is presumably readily ionizable 9 aque\s solutions4 ,alum9ium hydroxide1 z a base & z an acid1 w\ld yield 9 ! fir/ mom5t great] conc5trations ( ! hydroxide & hydrog5 ions ?an w\ld satisfy ! equilibrium con/ant = wat] 7p4 #agf72 ! excess ( ^! ions mu/ comb9e to =m wat]1 until ! product ( _! conc5trations is equal to ! ionization con/ant ( wat]4 ,! neutralization ( ^! fir/ quantities ( hydrog5 & hydroxide ions w\ld de/roy ! mom5t>y condition ( equilibrium betwe5 alum9ium hydroxide & its ions & w\ld lead to its fur!r ionization1 bo? z a base & z an acid1 & to ! solution ( "s alum9ium hydroxide 7see ! above equilibrium equations74 ,h[ev]1 s9ce ,al,o & ,al,o#b rema9 practically uncomb9$ & !re=e accumulate 9 ! solution1 ! conc5trations ( ! hydroxide & hydrog5 ions =m$ gr[ small] & small]2 = an increas+ excess ( ! ion ,al,o w all[ only small] & small] values = ,,ho1 accord+ to ! equilibrium equation = ,k,base1 &1 simil>ly1 an increas+ excess ( ! ion ,al,o#b w p]mit ,h to rea* only small] & small] values1 accord+ to ! equilibrium equation = ,k,acid4 ,:5 ! values = ,,ho & ,h h 9 ?is way become small en\gh to make ,,ho ,h ,k,,hoh1 equilibrium is rea*$4 ,x is evid5t t 9 su* a solution1 9 ! condition ( equilibrium1 ,,ho is n equal to ,al,o1 z x w\ld ord9>ily be1 accord+ to ! ionization equation ,al7,,oh7#c ,al,o ,,ho ,h#b,o1 b is mu* small]4 ,simil>ly1 ,h is mu* small] ?an ,al,o#b4 ,j h[ mu* alum9ium alum9ate mu/ be =m$ by a self-neutralization ( ! amphot]ic hydroxide w dep5d on ! values = ,k,base & ,k,acid & on ! solubility ( alum9ium hydroxide 7nonioniz$ ,al7,,oh7#c74 ,! two equilibrium equations may be comb9$3 ,al,o ,al,o#b ,h ,,ho _/ ,al7,,oh7#cb ,k,base ,k,acid4 p#ahh ,s9ce ,h ,,ho ,k,,hoh1 & s9ce ,al,o & ,al,o#b may be tak5 to repres5t ea* ! conc5tration ( ! practically completely ioniz$ alum9ium alum9ate ,al,o7,al,o#b71 we h#cgi ,alum4 ,alum9ate#b _/ ,alum4 ,hydroxide#b 7,k,base ,k,acid7 _/ ,k,,hoh1 or ,alum4 ,alum9ate _/ ,alum4 ,hydroxide 7,k,base ,k,acid7 _/ ,k,,hoh4 ,x is cle>1 t ! small] ! ionization con/ants ,k,base & ,k,acid are1 & ! small] ! solubility ( nonioniz$ alum9ium hydroxide ,alum4 ,hydroxide is1 ! small] mu/ be ! conc5tration ( ! alum9ate =m$ to satisfy ! conditions = equilibrium4 ,alum9ium hydroxide is a typical amphot]ic hydroxide1 & ! relations develop$ may be appli$1 mutatis mut&is1 to ! conditions ( equilibrium = analog\s amphot]ic hydroxides1 su* z z9c1 lead1 *romic hydroxides1 & s =?4 ,salt =mation or self-neutralization w dep5d1 9 e in/ance1 on ! /r5g? ( ! base & ! acid =m$1 & on ! solubility ( ! hydroxide4#chj ,) ! aid ( ! prec$+ consid]ations ! analytical reactions ( alum9ium1 :i* are us$ to sep>ate x f o!r elem5ts & to id5tify x1 may be readily und]/ood4 ,!y w be discuss$ 9 connection ) ! analysis ( ! ,alum9ium & ,z9c ,gr\ps4 ,! ,analysis ( ! ,alum9ium & ,z9c ,gr\ps4--,! gr\ps ( metals :i* are "h call$ ! p#ahi ,alum9ium & ,z9c ,gr\ps consi/ ( two gr\ps1 :i* ord9>ily are precipitat$ toge!r 9 qualitative analysis1 & :i* are !n sep>at$ f ea* o!r4 ,we may di/+ui% ! ,alum9ium ,gr\p ( trival5t metal ions1 includ+ alum9ium1 f]ric & *romium ions1 & ! ,z9c ,gr\p ( bival5t metal ions1 includ+ z9c1 nickel\s1 cobalt\s1 mangan\s & f]r\s ions4 ,( ! two gr\ps1 ! ions ( ! second gr\p1 9 agreem5t ) _! l[] val5ce 7see p4 #agb71 =m ! /rong] bases1 &1 z su*1 !y are all capable ( =m+ comp>atively /able salts ev5 ) su* v weak acids z hydrog5 sulphide & c>bonic acid4 ,ammonium sulphide1 add$ to a solution ( a salt ( any "o ( ! ions ( ! z9c gr\p1 precipitates ! correspond+ sulphide1 sodium or ammonium c>bonate precipitates ! correspond+ c>bonate4#cha ,we h1 = in/ance3 ,fe,cl#b 7,,nh#d7b,s ,fe,s #b ,,nh#d;,cl1 ,fe,cl#b ,na#b;,,co#c ,fe,c,o#c #b ,na,cl4 ,only "o memb] ( ?is gr\p1 z9c1 =ms an amphot]ic hydroxide & advantage is tak5 ( ?is 9 id5tify+ z9c4 ,! memb]s ( ! alum9ium gr\p =m hydroxides1 :i* are mu* weak] bases ?an are ! hydroxides ( ! bival5t gr\p j consid]$4 ,_! salts ) /rong acids are consid]ably hydrolyz$ & react /rongly acid1 & _! salts ) v weak acids1 l c>bonic acid & hydrog5 sulphide1 are decompos$ s readily by wat]1 t only f]ric sulphide is capable ( exi/5ce 9 its pres5ce4 ,:5 ! sulphide1 ,al#b,s#c1 prep>$ by heat+ alum9ium ) sulphur1 is add$ to wat]1 x is totally decompos$ into ! hydroxide & hydrog5 sulphide 7p4 #ahf72 & if alum9ium *loride is treat$ ) ammonium sulphide 9 aque\s solution1 alum9ium hydroxide1 & n its sulphide1 is precipitat$4 ,! latt] result may be int]pret$ 9 two ways1 bo? ( :i*1 9 ! ultimate analysis1 mean t hydrog5 sulphide is too weak an acid to =m a /able sulphide ) alum9ium hydroxide 9 ! pres5ce ( wat]1 ! difficult solubility ( alum9ium hydroxide & ! limit$ solubility ( hydrog5 sulphide be+ favor+ factors 7see p4 #ahf74 ,9 a solution ( alum9ium *loride1 ! salt ( a v weak base ) a /rong p#aij acid1 m or less ( ! salt is hydrolyz$1 & we h a condition ( equilibrium z express$ 9 ! equation ,al,cl#c #c ,h#b,o ,al7,,oh7#c #c ,h,cl4 ,! addition ( ammonium sulphide to su* a solution w\ld neutralize ! free hydro*loric acid1 & ! action w\ld proce$ to completion t[>ds ! "r1 hydrog5 sulphide be+ lib]at$1 by ! action ( ! acid on ! ammonium sulphide4 ,z hydrog5 sulphide is too weak an acid to comb9e1 appreciably1 ) alum9ium hydroxide1 & z ! latt] is difficultly soluble1 ! hydroxide is precipitat$4 ,accord+ to ! degree ( dilution1 m or less ( ! hydrog5 sulphide also escapes4 ,besides ?is int]pretation ( ! precipitation ( alum9ium hydroxide "u ^! conditions1 we may also consid] ! foll[+3 any alum9ium sulphide1 =m$ ! fir/ mom5t1 w\ld rema9 l>gely ioniz$ & w\ld be imm$iately conv]t$1 by ! ions ( wat]1 into alum9ium hydroxide & hydrog5 sulphide4 ,! net result ( ! action is ! precipitation ( alum9ium hydroxide & ! evolution ( hydrog5 sulphide3 #b ,al,cl#c #c 7,,nh#d7b,s #f ,h#b,o #b ,al7,,oh7#c #f ,,nh#d;,cl #c ,h#b,s or #b ,al#c #c ,s#b #f ,,hoh #b ,al7,,oh7#c #c ,h#b,s 4 ,a simil> result is obta9$ :5 ! solution ( a *romium salt is treat$ ) a solution ( ammonium sulphide4 ,only f]ric hydroxide is capable ( =m+ a sulphide1 f]ric sulphide1 ,fe#b,s#c1 :i* is precipitat$ :5 solutions ( f]ric salts are treat$ ) ammonium sulphide4#chb ,ammonium sulphide w1 consequ5tly1 precipitate alum9ium & *romium hydroxides & f]ric1 f]r\s1 nickel1 cobalt1 manganese & z9c sulphides1 f a solution ( ! *lorides ( ! metals4 ,n[1 bo? ! sulphides & ! hydroxides ( ! alkal9e e>?s & alkalies are suffici5tly soluble n to be precipitat$ by ammonium sulphide1 or by a mixture ( x ) ammonium hydroxide1 if ammonium *loride be add$ to ! mixture to prev5t ! precipitation ( magnesium hydroxide 7see p4 #afh71 :i* is ! lea/ soluble ( ! hydroxides ( ! alkal9e e>? gr\p4 p#aia ,a mixture ( ammonium sulphide1 ammonium hydroxide & ammonium *loride w1 !re=e1 precipitate ! alum9ium & z9c gr\ps toge!r1 sep>at+ !m f ! alkal9e e>? & alkali gr\ps4#chc ,sep>ation ( ! ,alum9ium ,gr\p f ! ,z9c ,gr\p by ,means ( ,ammonium ,*loride & ,ammonium ,hydroxide4--,! precipitation ( ! two gr\ps toge!r makes _! subsequ5t sep>ation necess>y4 ,"s analy/s attempt to avoid ! extra op]ations involv$1 by mak+ use ( ! fact t ! hydroxides ( ! bival5t gr\p1 al?\gh difficultly soluble1 are1 l magnesium hydroxide1 /ill suffici5tly soluble n to be precipitat$ by ammonium hydroxide 9 ! pres5ce ( suffici5t ammonium *loride1 :ile ! hydroxides ( ! trival5t metals ( ?is gr\p are s insoluble t !y may be precipitat$ quantitatively by su* a mixture 7p4 #agj74 ,! trival5t hydroxides may be fir/ precipitat$ by ammonium hydroxide1 9 ! pres5ce ( ammonium *loride1 &1 subsequ5tly1 ! sulphides ( ! bival5t metals may be precipitat$ by ammonium sulphide1 ! two precipitates be+ collect$ sep>ately4 ,! me?od has ! disadvantage t x is n always accurate4 ,! acid "* ( alum9ium & *romium hydroxides 7& ev5 ( f]ric hydroxide1 see p4 #aie71 z well z ( z9c hydroxide1 leads1 to a c]ta9 ext5t1 to ! precipitation1 f su* alkal9e solutions1 ( salts ( ^! amphot]ic hydroxides ) ! basic hydroxides ( ! bival5t gr\p2 ! latt] are ?us liable to be lo/ 9 ! analysis4 ,x w be recall$1 t ! equilibrium conditions 9 alkal9e solutions favor ! ionization ( amphot]ic sub/ances 9 ! acid =m 7,"p ,,iii71 & alkal9e solutions w\ld favor ! precipitation ( alum9ates1 *romites1 etc41 ( ! ions ( ! z9c gr\p4 ,me?ods h1 !re=e1 be5 devis$ to sep>ate ! two gr\ps 9 neutral1 or v slightly acid1 m$ia1 & !y give quantitative sep>ations & are pref]able to ! me?od j describ$4 ,! sep>ation by means ( susp5d$ b>ium c>bonate1 9 :i* c>bonic acid is lib]at$ & ! solution is practically neutral1 w be discuss$ bel[ on page #aic4 ,a second me?od1 frequ5tly us$ 9 quantitative analysis1 is bas$ on ! p#aib decomposition ( ! acetates ( ! alum9ium gr\p by boil+ wat]1 acetic acid be+ lib]at$4#chd ,sep>ation ( ,cobalt & ,nickel f ! ,o!r ,memb]s ( ! ,z9c & ,alum9ium ,gr\ps4--,:5 ! alum9ium & z9c gr\ps are precipitat$ toge!r1 by means ( a mixture ( ammonium sulphide1 hydroxide & *loride1 ! precipitate1 obta9$ f a solution conta9+1 say1 ! *lorides ( all ! ions ( ! gr\ps1 w\ld consi/ ( ! foll[+ comp\nds3 ,alum9ium ,gr\p3 ,fe#b,s#c1 ,al7,,oh7#c1 ,cr7,,oh7#c4 ,z9c ,gr\p3 ,ni,s1 ,co,s1 ,fe,s1 ,mn,s1#che ,zn,s4 ,if su* a precipitate is treat$1 9 ! cold1 = a %ort "t ) q dilute 7#a to #a4b mol>7 hydro*loric acid1 all ( ! hydroxides & sulphides dissolve1 except+ ! great] "p ( ! nickel & cobalt sulphides1 :i* dissolve v mu* m sl[ly ?an d ! o!r comp\nds4 ,advantage is tak5 ( ?is fact1 to sep>ate ^! two elem5ts f ! rema9+ memb]s ( ^! gr\ps1 & if ! treatm5t is c>ri$ out ) c>e1 ! sep>ation is usually satisfactory4 ,9 all cases1 h[ev]1 s9ce x is a "q ( delay$ solution only1 at lea/ traces1 & sometimes consid]ably m ?an traces1 ( ! sulphides ( nickel & cobalt g into solution ) ! o!r comp\nds4 ,no sacrifice ( analytical accuracy is involv$1 if ?is possible loss is kept 9 m9d & provision made = ! lat] detection ( ^! small quantities ( nickel & cobalt4 ,! "q ( ! sl[ solution1 or app>5t lack ( solubility1 ( nickel & cobalt sulphides 9 dilute hydro*loric acid has =m$ an int]e/+ problem = inve/igation4 ,:ile nickel & cobalt sulphides are precipitat$ by ammonium sulphide1 ^! sulphides1 9 common ) ^? ( all ! o!r memb]s ( ! z9c gr\p1 are n precipitat$ by hydrog5 sulphide 9 ! pres5ce ( a small excess ( hydro*loric acid4#chf ,we w\ld h p#aic ,ni,cl#b x ,h,cl ,h#b,s ,ni,s 7x #b7 ,h,cl z repres5t+ ! condition ( equilibrium1 if we />t ) nickel *loride1 hydro*loric acid & hydrog5 sulphide2 ! am\nt ( sulphide ,ni,s1 =m$1 is insuffici5t to sup]saturate ! solution & =m a precipitate4 ,9 rev]sible reactions ! f9al condition ( equilibrium mu/ be indep5d5t ( ! ord] 9 :i* compon5ts are mix$ 7p4 #ia71 a conclusion :i* is borne out by exp]i5ce4 ,"o %\ld expect1 !n1 t nickel sulphide1 :5 treat$ ) dilute hydro*loric acid1 w\ld dissolve & give nickel *loride1 hydrog5 sulphide & an excess ( acid1 & ?us produce ! same sy/em1 f\nd to be 9 equilibrium1 :5 "o />ts ) ! *loride1 hydrog5 sulphide & hydro*loric acid4 ,z a matt] ( fact1 ! same condition ( equilibrium is f9ally rea*$1 only x is rea*$ sl[ly1#chg mu* m sl[ly ?an ord9>ily 9 su* cases1 mu* m sl[ly1 = in/ance1 ?an ) f]r\s sulphide1 hydro*loric acid & hydrog5 sulphide 7exp474 ,by tak+ advantage ( ?is sl[ return to equilibrium & by work+ ) ! sy/em dur+ ! process ( sl[ *ange 7collect+ ! undissolv$ nickel & cobalt sulphides on a filt]71 "o c sep>ate ! sulphides ( nickel & cobalt f ! o!r compon5ts ( ! mix$ precipitate1 :i* dissolve mu* m rapidly4 ,sep>ation ( ! ,alum9ium & ,z9c ,gr\ps by ,means ( ,b>ium ,c>bonate4--,! solution1 obta9$ by treat+ ! mixture ( ! sulphides & hydroxides ( ! alum9ium & z9c gr\ps ) dilute hydro*loric acid 7p4 #aib71 conta9s alum9ium1 *romium1 mangan\s1 z9c & f]r\s *lorides1 all ! iron be+ n[ pres5t 9 ! f]r\s condition because ( ! r$uc+ action ( hydrog5 sulphide on ! f]ric-ion 7,"p ,,iii74 ,! *lorides ( nickel & cobalt are also pres5t 9 small quantities 7see above74 ,! fur!r treatm5t ( ! solution is direct$ t[>d a sep>ation ( ! bival5t ions ( ! z9c gr\p f ! trival5t ions ( ! alum9ium gr\p1 & ! int5tion is to h all ! iron g ) ! trival5t metals4 ,! f]r\s is1 !re=e1 oxidiz$ to ! f]ric-ion4 ,aft] a "p ( ! solution has be5 te/$ to %[ ! pres5ce or abs5ce ( f]ric salts1 ! two gr\ps are sep>at$ by means ( a susp5sion1 9 wat]1 ( f9ely p#aid divid$ b>ium c>bonate4 ,! !ory ( ! sep>ation may be develop$ z foll[s3 ,:5 z9c *loride1 :i* may be tak5 z a repres5tative ( ! bival5t gr\p1 is treat$ ) sodium c>bonate1 a difficultly soluble c>bonate is precipitat$1 s9ce z9c hydroxide1 l ! rema9+ bival5t hydroxides1 is a suffici5tly /rong base to =m a fairly /able c>bonate4#chh ,:5 f]ric *loride1 a repres5tative ( ! trival5t gr\p1 is treat$ ) a solution ( sodium c>bonate1 f]ric hydroxide1 mix$ ) "s basic f]ric c>bonate#chi ,fe#b7,,oh7#d;,,co#c1 is precipitat$ & c>bon dioxide escapes 7exp474 ,! trival5t hydroxides are too weak bases#cij to =m /able salts ) s weak an acid z c>bonic acid4 #b ,fe,cl#c #c ,na#b;,,co#c #f ,h#b,o #b ,fe7,,oh7#c #c ,h#b;,,co#c #f ,na,cl #c ,h#b;,,co#c #c ,h#b,o #c ,,co#b 4 ,s9ce ! bival5t metal ions are precipitat$ by sodium c>bonate z c>bonates & ! trival5t ones z hydroxides1 ! reag5t1 obvi\sly1 _c be us$ to sep>ate ! two gr\ps4 ,b b>ium c>bonate is s little soluble 9 wat] t x w n precipitate mangan\s1 z9c1 nickel1 cobali\s & f]r\s c>bonates#cia f solutions ( _! *lorides or nitrates4 ,we h1 = in/ance1 ,zn,cl#b ,ba,c,o#c ,ba,cl#b ,zn,c,o#c4 ,b>ium c>bonate has1 h[ev]1 ! same effect on f]ric *loride 7exp47 & on ! o!r *lorides ( ! trival5t gr\p1 z has sodium c>bonate1 i4e4 x precipitates _! hydroxides4 ,by means ( b>ium c>bonate p#aie we c1 !re=e1 precipitate ! hydroxides ( ! alum9ium gr\p )\t precipitat+ ! ions ( ! z9c gr\p4 ,! sep>ation is c>ri$ out 9 a1 practically1 neutral m$ium 7free c>bonic acid 9 excess is evolv$2 b>ium c>bonate alone1 :5 treat$ ) wat]1 is slightly alkal9e7 & ?us avoids ! error ( facilitat+ ! precipitation ( ! bival5t metals 9 ! %ape ( salts ( ! acidic =ms ( ! trival5t metals1 i4e4 z alum9ates1 *romites1 & s =?4 ,mangan\s salts are liable to oxidation to manganic salts1 :5 expos$ to ! air1 especially 9 alkal9e1 neutral or slightly acid solutions1 & prolong$ exposure ( ! b>ium c>bonate mixture to ! air may result 9 ! precipitation ( manganic hydroxide1 ,mn7,,oh7#c1 ) ! o!r trival5t hydroxides4 ,provision is made = its detection 9 ! sy/ematic analysis4 ,analysis ( ! ,alum9ium ,gr\p4--,! precipitate ( ! alum9ium gr\p may conta9 alum9ium1 *romium & f]ric hydroxides 7possibly traces ( manganic hydroxide7 & _! basic c>bonates4 ,a color te/ = f]ric-ion has already be5 made 7see p4 #aic7 & *romium 7& manganese7 is readily f\nd & id5tifi$ by oxidation to ! int5sely color$ salts ( *romic 7& manganic7 acid 7,"p ,,iii1 q4v474 ,9 asc]ta9+ :e!r alum9ium hydroxide is pres5t or n1 advantage is tak5 ( its amphot]ic "*4 ,*romium hydroxide1 l alum9ium hydroxide1 is amphot]ic2 b1 9 agreem5t ) ! great] atomic weight ( *romium1 x is an ev5 weak] acid ?an is alum9ium hydroxide4 ,its sodium salt1 sodium *romite1 is completely decompos$ by boil+ wat]1 *romium hydroxide be+ precipitat$ 9 a less hydrat$1 insoluble =m4 ,f]ric hydroxide1 ^: metal has ! highe/ atomic weight ( ! ?ree elem5ts "u consid]ation1 has s little acid "*1 t x is n p]ceptibly soluble 9 solutions ( potassium or sodium hydroxide4 7,t x has slight acidic prop]ties is %[n by its capacity to =m f]rites1 e4g4 ,me7,fe,o#b7b1 :i* may be/ be obta9$ by dry me?ods1 & ( :i* f]r\s f]rite or magnetic iron ore1 ,fe#c,o#d or ,fe7,fe,o#b7b1 is ! mo/ important repres5tative47 ,( ! ?ree hydroxides1 alum9ium hydroxide is1 !re=e1 ! only "o t w dissolve 9 boil+ sodium hydroxide4 ,9 ?is solution we c be/ id5tify x1 by conv]t+ ! alum9ate into an alum9ium salt1 by means ( an excess ( acid1 p#aif & by a f9al precipitation ( alum9ium hydroxide ) ammonium hydroxide4 ,alum9ium hydroxide is too weak an acid to =m a /able alum9ate ) s weak a base z ammonium hydroxide1 :5 ! latt] is us$ only 9 slight excess 7p4 #ahf74 ,if we attempt to prep>e ammonium alum9ate1 by add+ ammonium *loride to a solution ( sodium alum9ate1 a precipitate ( alum9ium hydroxide is obta9$ 7exp474 ,= exact "w1 an excess ( ammonium hydroxide is to be avoid$ & its /r5g? z a base %\ld be weak5$ by ! addition ( "s ammonium *loride or nitrate 7pp4 #aad1 #afi & ,lab4 ,manual1 p4 #i1 #f74 ,we h1 9 ?is in/ance1 ! case ( a v weak1 difficultly soluble acid1 alum9ium hydroxide1 =m+ a salt ) a weak1 soluble base1 ammonium hydroxide4 ,! conditions det]m9+ ! solubility ( alum9ium hydroxide 9 ammonium hydroxide1 z an alum9ate ,,nh#d;,al,o#b1 may be %[n z foll[s3 = ! acid ionization ( alum9ium hydroxide1 ,al7,,oh7#c ,al,o#b ,h ,h#b,o 7p4 #agb72 ! solubility-product = a saturat$ solution is ,al,o#b ,h ,k,ac4,s4,p44 ,fur!r1 f ,h ,,ho ,k,,hoh1 we f9d ,h ,k,,hoh _/ ,,ho4 ,!n ,al,o#b ,,ho ,k,ac4,s4,p4 _/ ,k,,hoh1 :i* %[s t ! solubility ( alum9ium hydroxide1 z alum9ate1 is proportional to ! conc5tration ,,ho ( ! hydroxide-ion 9 ! solution4 ,= ,,nh#d,,oh we h ,,nh#d ,,ho _/ 7,,nh#c ,,nh#d,,oh7 #j4jjj1jah 7p4 #afa71 & consequ5tly1 ,,ho #j4jjj1jah 7,,nh#c ,,nh#d,,oh7 _/ ,,nh#d4 ,!n ,,ho is ! small]1 ! small] ! excess ( ammonium hydroxide us$ 7:i* is approximately equal to 7,,nh#c ,,nh#d,,oh77 & ! great] ! conc5tration ,,nh#d ( ! ammonium-ion1 i4e4 ( ! add$ ammonium salt4 ,! solubility ( ,al7,,oh7#c1 z alum9ate1 9 ammonium hydroxide & ammonium *loride is1 !re=e1 directly proportional to ! excess ( ammonium hydroxide1 & indirectly proportional to ! conc5tration ( ! ammonium salt pres5t4#cib ,! ,favorable ,conditions = a ,maximum ,precipitation ( an ,amphot]ic ,hydroxide4--,! precipitation ( alum9ium hydroxide dep5ds also on ! solubility-product ( alum9ium hydroxide1 ioniz$ z a base4 ,= ,al7,,ho7#c ,al#c #c ,,ho1 9 a saturat$ solution1 ,al#c ,,ho#c ,k,bas4,s4,p44 ,x is evid5t1 t an excess ( ! precipitat+ hydroxide-ion w\ld be favorable to ! precipitation 9 ?is =m1 & t ! r$uction ( ! conc5tration ( ! hydroxide-ion1 :ile act+ favorably1 z j %[n1 9 prev5t+ ! solution ( ! hydroxide z an alum9ate1 mu/ be1 to "s ext5t1 detrim5tal to a maximum precipitation ( ! hydroxide z a base4 ,"o may ask1 !re=e1 :at ! mo/ favorable conc5tration ( ! hydroxide-ion mu/ be = a quantitative precipitation ( alum9ium hydroxide4 ,! problem may be treat$ z foll[s3 ,accord+ to ! solubility-product relation = ! basic ionization1 we h1 9 a solution saturat$ ) alum9ium hydroxide1 p#aig ,al#c ,k,bas4,s4,p4 ,,ho#c4 ,i ,= ! sake ( a c]ta9 simplicity 9 ! result1 we w1 = ! mom5t1 consid] alum9ium hydroxide to ionize z an acid accord+ to ,al7,,ho7#c ,al,o#cc #c ,h1 :i* w\ld resemble ! basic ionization4 ,!n we w\ld h ,al,o#cc ,h#c ,k,ac4,s4,p41 &1 us+ ! relation ,h ,k,,hoh _/ ,,ho1 we h ,al,o#cc ,,ho#c ,k,ac4,s4,p4 ,k,,hoh#c4 ,,ii ,add+ equations ,i & ,,ii we f9d ,al#c ,al,o#cc ,k,bas4,s4,p4 ,,ho#c ,,ho#c ,k,ac4,s4,p4 ,k,,hoh#c ,,iii ,alum9ium hydroxide w be mo/ completely precipitat$ :5 ,al#c ,al,o#cc is a m9imum1 ! values ,al#c & ,al,o#cc measur+ ! solubility ( alum9ium z alum9ium-ion & z alum9ate-ion4 ,if we put ,al#c ,al,o#cc y & ,,ho x1 we c f9d ! value x 7! conc5tration ( ! hydroxide-ion7 = :i* y is a m9imum4 ,we h y ,k,bas4,s4,p4 x#c x#c ,k,ac4,s4,p4 ,k,,hoh#c1 & f9d1 by means ( ! calculus1#cic t y is a m9imum1 :5 x 7,k,,hoh#c ,k,bas4,s4,p4 _/ ,k,ac4,s4,p47#a_/f4 ,if alum9ium hydroxide 7 z /rong an acid z x is a base1 i4e4 if ,k,bas4,s4,p4 ,k,ac4,s4,p41 we w\ld h1 simply1 x ,,ho 77#a4b;,e#ad7c7a_/f 7#a4b;,e#ad7 7at #be71 :i* is ! conc5tration ( ! hydroxide-ion 9 pure wat] at #be 7p4 #agf74 ,9 o!r words1 a p]fectly neutral solution w\ld !n give u ! conditions = z complete a precipitation z possible4 ,b alum9ium hydroxide is a /rong] base ?an acid1 ,k,bas4,s4,p4 ,k,ac4,s4,p41 & consequ5tly we f9d = x ,,ho 7,k,,hoh#c ,k,bas4,s4,p4 _/ ,k,ac4,s4,p47#a_/f1 a value some:at great] ?an ! conc5tration ( ! hydroxide-ion 9 pure wat]1 i4e4 we mu/ use a slightly alkal9e m$ium--:i* agrees ) common practice4 ,9 o!r words1 !re is less dang] ( los+ alum9ium hydroxide 9 ! =m ( alum9ate1 ow+ to ! weak] acid "* ( ! hydroxide1 ?an !re is ( los+ x 9 ! =m ( alum9ium-ion4 ,! mo/ favorable degree ( alkal9ity = ! precipitation w\ld dep5d on ! relation ( ,k,bas4,s4,p44 & ,k,ac4,s4,p44 ,! exact values = ,k,bas4,s4,p4 & ,k,ac4,s4,p41 ! two solubility-product con/ants1 & = ! correspond+ ionization con/ants1 :i* w\ld %[ ! same ratio1 are /ill n kn[n4 ,b1 if1 = ! sake ( an illu/ration1 we take rec\rse to assum$ values = ^! con/ants1 we f9d t ! solubility ( alum9ium1 z alum9ium-ion & z alum9ate-ion1 is1 by calculation1 z anticipat$1 a m9imum = a solution1 :i* conta9s ! conc5tration ( ,,ho calculat$ 7= x7 9 ! mann] indicat$ above4 ,& ! fur!r int]e/+ conclusion is rea*$ t ?is m9imum loss ( alum9ium p#aih hydroxide w\ld occur :5 ,al#c ,al,o#cc--:i* w\ld correspond to a saturat$ solution ( alum9ium alum9ate1 ,al7,al,o#c74 ,:5 ! ionization ( alum9ium hydroxide1 z an acid1 is consid]$ to take place accord+ to ,al7,,oh7#c ,al,o#b ,h ,h#b,o1 :i* agrees be/ ) its real behavior 7p4 #agb71 we c f9d1 simil>ly1 t ,al#c ,al,o#b is a m9imum1 :5 alum9ium hydroxide is precipitat$ 9 su* a way1 t an excess x ( ! hydroxide-ion is us$1 & x ,,ho 7#c ,k,,hoh ,k,bas4,s4,p4 _/ ,k,ac4,s4,p47#j4be1--:]e ,k,ac4,s4,p4 repres5ts ! solubility-product con/ant = ,al,o#b ,h4 ,t a m9imum loss ( alum9ium hydroxide w\ld be suff]$ :5 ! favorable excess ( ! hydroxide-ion 7x7 is calculat$ on ! basis ( ! equation z giv51 may readily be se5 by aga9 assum+ def9ite values = ,k,bas4,s4,p4 & ,k,ac4,s4,p44 ,x also appe>s t ?is m9imum loss#cid ( alum9ium includes "o-?ird z _m ,al#c ions1 z ,al,o#b ions--a relation correspond+1 aga91 to a saturat$ solution ( alum9ium alum9ate1 ,al7,al,o#b7c4 ,,footnotes3 #ced ,:5 all ?ree ( ! hydrog5 atoms 9 ! hydroxide are ioniz$1 an alum9ate ion1 ,al,o#cc is =m$3 ,al7,,oh7#c ,al,o#cc #c ,h4 ,b1 z 9 ! case ( o!r weak polybasic acids1 a s+le hydrog5 atom is f> m readily ioniz$ ?an are ! rema9+ two 7p4 #ajb71 & ! ion ,al7,,oh7#b,o1 :i* is =m$ by ! prim>y ionization1 readily loses wat] & =ms ! anhydride ion ,al,o#b4 ,! mo/ important alum9ates are d]ivatives ( ?is ion4 #cee ,see ! table at ! back ( ,smi?'s ,inorganic ,*emi/ry1 or p4 #adi ( ,rems5's ,inorganic ,*emi/ry4 #cef ,! displacem5t ( hydrog5 by a metal1 l sodium1 is ! result ( ! displacem5t ( ! hydrog5-ion 7see ,*apt]s ,,xiv & ,,xv74 ,! hydrog5-ion 9 fus$ sodium hydroxide is probably =m$ *iefly by ! second>y ionization ( ! hydroxide-ion 7,,ho ,h ,o#b7 7see ,*ap4 ,,xiii74 ,we _c h positive ions1 ,na1 ) negative ions1 ,o#b1 )\t hav+ "s ions ,na,o4 7,o#b ,na ,na,o71 ,na,o,h1 und\bt$ly1 is mu* too weak an acid to =m salts ) bases 9 ! pres5ce ( wat]4 ,su* salts w\ld be decompos$ by wat] 7see bel[1 p4 #ahj71 z sodium oxide1 inde$1 is decompos$2 we h ,na--,o--,na ,,hoh #b ,na,o,h 7see ,*apt] ,,xiii = a detail$ discussion ( ?is action74 ,^! relations suffici5tly acc\nt = ! fact t salts ( sodium hydroxide1 9 :i* x has ! functions ( an acid1 are n commonly =m$4 7,cf4 ,abegg1 ,anorganis*e ,*emie1 ,,ii1 7#a7 p4 #bdg47 #ceg ,see ,j4 ,j4 ,?omson1 ,corpuscul> ,!ory ( ,matt]1 pp4 #ajc-ada4 #ceh ,see ,m5deleff1 ,pr9ciples ( ,*emi/ry1 ,i1 #bb 7#ahia71 9 reg>d to ! rle ( ev5 & unev5 s]ies 9 ! sy/em4 #cei ,9 reg>d to ! indications ( ! amphot]ic "* ( /rong] acids1 see ,*apt] ,,xv4 #cfj ,an elaborate treatm5t ( ?is problem is giv5 by ,walk]1 ,z4 phys4 ,*em41 #di1 #hb 7#aijd71 #ea1 #gjf 7#aije74 #cfa ,kohlraus* & ,heydweill]1 ,z4 phys4 ,*em41 #ad1 #cag 7#ahid74 #cfb ,see ! table1 p4 #ajd4 #cfc ,see p4 #ec & van 't ,h(f's rem>ks1 ibid4 #cfd ,?is sugge/s a mu* broad]1 natural def9ition ( a base ?an ! conv5tional "o4 ,all salts ( v weak acids1 to a c]ta9 degree1 :i* is det]m9$ by ! weakness ( _! acids1 d exactly :at ! ord9>y bases d1 e4g4 neutralize acids4 ,metal d]ivatives ( acids weak] ?an wat]1 metal amides1 l ,zn7,,nh#b7b1 metal alkyls1 l z9c me?yl1 ,zn7,,*#c7b1 react m vigor\sly ?an ! hydroxides d1 e4g4 9 neutraliz+ acids1 & wat] attacks !m & acts ^u !m1 exactly z ord9>y acids int]act ) metal hydroxides4 ,we h1 = in/ance1 ,zn7,,*#c7b #b ,,hoh ,zn7,,oh7#b #b ,,*#d4 #cfe ,see footnote1 p4 #agg4 ,simil> consid]ations apply to ! conv5tional def9ition ( an acid4 #cff ,! symbols 9 heavy type indicate ! *ief compon5ts ( ! f9al sy/em4 ,vide ,smi?'s ,g5]al ,*emi/ry = ,colleges & ,inorganic ,*emi/ry1 = ! =m ( equations us$4 #cfg ,emi*1 ,b]4 d4 *em4 ,ges4 #dj1 #adhb 7#aija74 #cfh ,arrh5ius1 ,z4 phys4 ,*em41 #e1 #af 7#ahij72 ,%ields1 ibid41 #ab1 #afg 7#ahic74 #cfi ,see bel[ = ! correspond+ equation1 develop$ by ,walk] = a salt ( a weak base & a /rong acid4 #cgj ,potassium sulphate1 ,k#b,,s#d1 reacts fa9tly alkal9e 9 aque\s solution1 ! second>y ionization ( sulphuric acid 7table1 p4 #ajd7 be+ some:at weak] ?an ! ionization ( potassium hydroxide4 ,we h3 ,k#b,,s#d ,,hoh ,,khso#d ,,koh or ,,s#db ,,hoh ,,hso#d ,,ho4 #cga ,walk]1 ,z4 phys4 ,*em41 #d1 #cai1 7#ahhi72 ,arrh5ius1 loc4 cit42 ,br$ig1 ibid41 #ac1 #cba 7#ahid74 #cgb ,arrh5ius1 loc4 cit4 #cgc ,see p4 #ahc4 #cgd ,arrh5ius develop$ ! relation = anil9e acetate1 loc4 cit4 #cge ,putt+ x ,acid ,base1 we h ,salt 7#j4a x71 & 7#j4a x7#b _/ x#b 7#g;,e#aj7b _/ #a4b;,e#ad4 ,!n 7#j4a x7 _/ x #j4jjfd & x 4#jiice1 :i* is #ii4ce ( ! total salt us$4 ,! degree ( ionization1 1 ( ! salt1 9 ! extremely dilute solution1 is tak5 to be #ajj4 #cgf ,see ! equations = ,k,base & ,k,acid1 on p4 #ahd1 & _! premises4 #cgg ,see p4 #agb4 ,! conc5tration ( wat] may be consid]$ a con/ant & is includ$ 9 ,k,acid 7& ,k,base1 bel[74 #cgh ,only ! prim>y ionization 7( alum9ium hydroxide7 is consid]$ 9 ! text1 because only t is involv$1 z a rule1 9 ! neutralization ( v weak bases by v weak acids 7see footnote #b1 p4 #aid74 ,! relations are also simpl] & cle>]1 if we limit ! discussion to ! =mation ( a salt ,al,o7,al,o#b74 #cgi ,see ! simil> equation1 p4 #ahe4 #chj ,amphot]ic sub/ances ( a diff]5t class are also kn[n1 :i* h1 at ! same "t1 mod]ately /rong acid & mod]ately /rong basic functions4 ,glycocoll1 ,h#b,n4,,*#b;,,cooh1 a d]ivative ( acetic acid & ammonia1 conta9s an acid gr\p1 ! --,,cooh gr\p1 ! hydrog5 ( :i* is approximately z ionizable z ! hydrog5 9 ! correspond+ gr\p 9 acetic acid1 ,,*#c;,,cooh4 ,! ammonia residue1 ,h#b,n--1 9 glycocoll1 =ms ) wat] a hydroxide1 correspond+ to ammonium hydroxide1 :i* likewise is approximately z ionizable z is ammonium hydroxide4 ,9 ! hydroxide ( glycocoll we h1 consequ5tly1 bo? a mod]ately /rong acid1 & a mod]ately /rong basic1 gr\p4 ,9 ?is1 & 9 simil> cases1 salt =mation betwe5 ! acid & ! basic gr\ps ( ! amphot]s takes place to z great an ext5t z if ! functions 7 attributes ( di/9ct comp\nds4 ,glycocoll 9 aque\s solution is pres5t1 !n1 *iefly 9 ! =m ( a salt1 = in/ance1 ,h#c,n4,,*#b4;,,coo1 correspond+ to ammonium acetate1 ,,*#c;,,coonh#d4 ,= an elaborate discussion ( ! equilibrium conditions 9 solutions ( amphot]ic comp\nds vide ,walk]1 ,z4 phys4 ,*em41 #di & #ea4 #cha ,! c>bonates are occasionally p>tially hydrolyz$ to basic c>bonates4 #chb ,/okes1 ,j4 ,am4 ,*em4 ,soc41 #bi1 #cjd 7#aijg74 #chc ,a complication1 :i* leads to ! precipitation ( alkal9e e>?s1 along ) ^! gr\ps1 z phosphates & simil> insoluble salts 7n z hydroxides or sulphides71 :5 phosphate or c]ta9 o!r acid ions are pres5t1 is treat$ 9 ,"p ,,iv 7q4v47 "u ! sy/ematic analysis ( ! gr\ps4 #chd ,cf4 ,fres5ius1 ,quantitative ,analysis4 #che ,ammonium sulphide usually precipitates a p9k hydrat$ sulphide ( manganese1 probably ,mn7,,%77,,oh74 ,"u c]ta9 conditions ( conc5tration & temp]ature1 ! d>k gre5 sulphide ,mn,s is precipitat$4 ,9 quantitative "w ! *emi/ aims to precipitate ?is gre5 sulphide1 :i* is m easily collect$ on a filt]4 7,cf4 ,fres5ius1 ,quantitative ,analysis47 #chf ,we %all f9d t ?is prop]ty ( ! :ole z9c gr\p makes x possible to sep>ate ! foll[+ gr\ps1 ! copp] & ars5ic gr\ps1 f ! z9c gr\p 7see p4 #aeh74 ,! !ory ( ! sep>ation w be discuss$ 9 detail 9 ,*apt] ,,xi4 #chg ,vide ,noyes1 ,bray & ,spe>1 ,j4 ,am4 ,*em4 ,soc41 #cj1 #dhc 7#aijh74 #chh ,see footnote1 p4 #ahi4 #chi ,! comp>ative /ability ( ?is basic salt repres5ts an in/ance ( ! diff]5t ioniz+ p[]1 or basic /r5g?1 ( ! ?ree hydroxide gr\ps ( a trival5t base 7see p4 #ajf74 ,! hydrolysis ( f]ric *loride seems to involve1 prim>ily1 only ! ?ird or lea/ ionizable ( ! hydroxide gr\ps ( f]ric hydroxide1 & ! hydrolysis1 except 9 extreme dilution1 proce$s *iefly accord+ to ,fe#c #c ,cl ,,hoh ,fe7,,oh7#b #c ,cl ,h4 ,vide ,goodw91 ,z4 phys4 ,*em41 #ba1 #a 7#ahif74 ,9 ! case ( ! salt ( ! mu* weak] acid1 c>bonic acid1 ! hydrolysis goes fur!r1 involv+ two hydroxide gr\ps ( f]ric hydroxide &1 to "s ext5t1 all ?ree4 #cij ,! extreme insolubility ( ,al7,,oh7#c1 ,fe7,,oh7#c & ,cr7,,oh7#c1 toge!r ) _! weakness z bases1 facilitates _! precipitation 7see pp4 #ahe-f74 #cia ,!re is a small degree ( hydrolysis 7see footnote1 p4 #ahi71 b ! hydroxides ( ! z9c gr\p are n suffici5tly insoluble to be precipitat$ "u ^! conditions4 #cib ,cf4 ,a4 ,a4 ,noyes1 ,bray & ,spe>1 ,j4 ,am4 ,*em4 ,soc41 #cj1 #dif 7#aijh74 #cic ,cf4 ,! ,elem5ts ( ! ,diff]5tial & ,integral ,calculus1 bas$ on ,n]n/ & ,s*nflies's ,lehrbu*1 etc41 by ,"y & ,l9eb>g]1 pp4 #cfc & #cfd 7#aijj74 #cid ,losses due to ! t5d5cy ( alum9ium hydroxide to assume ! colloidal condition 7p4 #acf7 mu/ be gu>d$ aga9/ by o!r precautions 7loc4 cit474 p#aii ,,*apt] ,,xi ,,! ,,copp] ,,& ,,silv] ,,gr\ps4 ,,precipitation ,,) ,,hydrog5 ,,sulphide ,! sulphides ( ! metal ions ( ! z9c gr\p are readily precipitat$ by ammonium or sodium sulphide1 b hydrog5 sulphide1 9 ! pres5ce ( a small excess ( a /rong acid1 su* z hydro*loric acid1 does n precipitate any ( ^! sulphides 7or any ( ! sulphides ( ! alum9ium1 ! alkal9e e>? & ! alkali gr\ps74 ,"u ! same conditions ! sulphides ( ! metal ions ( ! silv] gr\p1 ,ag1 ,hg1 ,pb#b1 ( ! copp] gr\p1 ,hg#b1 ,pb#b1 ,bi#c1 ,cu#b1 ,cd#b1 & also ( ! ars5ic gr\p1 ,z#c1 ,z#e1 ,sb#c1 ,sb#e1 ,sn#b1 ,sn#d1 ,pt#b1 ,pt#d1 ,au1 & ,au#c1 are precipitat$4 ,advantage is tak5 ( ^! relations 9 ! foll[+ way1 9 sy/ematic analysis3 aft] ! sep>ation ( ! silv] gr\p1 by precipitation ( ! difficultly soluble *lorides1 hydrog5 sulphide1 9 ! pres5ce ( an excess ( acid1 is us$ to precipitate ! sulphides ( ! ions ( ! copp] & ! ars5ic gr\ps1 ! two gr\ps be+ precipitat$ toge!r4 ,hydrog5 sulphide1 "u ^! conditions1 does n precipitate any sulphides ( ! z9c gr\p or ^? ( any ( ! rema9+ gr\ps4 ,hydrog5 sulphide is us$1 9 ?is way1 z "o ( ! mo/ valuable reag5ts 9 analytical "w1 enabl+ ! analy/ to sep>ate :ole gr\ps ( metal ions f o!r gr\ps4 ,!re is also no o!r ag5t1 equally important1 :i* is m likely to be us$ 9 a wrong way & to lead to error4 ,! ,ionization ( ,hydrog5 ,sulphide4--,be=e tak+ up ! !ory ( ! sep>ation ( ^! gr\ps by precipitation ) hydrog5 sulphide 9 ! pres5ce ( a /rong acid1 a discussion ( "s ( ! *>act]i/ics ( ! reag5t w be 9 place4 ,hydrog5 sulphide1 l c>bonic acid & o!r dibasic acids1 ionizes 9 two /ages2 x produces fir/ hydrog5-ion & hydrosulphide-ion1 ,,hs1 & ?is ion 9 turn dissociates1 produc+ hydrog5-ion & sulphide-ion1 ,s#b4 p#bjj ,= ! fir/ dissociation1 ,,h% ,h ,,hs1 we h ,h ,,hs _/ ,h#b,s ,k#a 7,i7 ,! value ( ! con/ant#cie = ?is prim>y ionization ( hydrog5 sulphide is #j4ia;,e#g4 ,x is app>5t t hydrog5 sulphide1 ev5 9 ! prim>y ionization1 is a v weak acid & produces a v small conc5tration ( hydrosulphide-ion4 ,9 a solution1 saturat$ at #be1 ! total conc5tration ( hydrog5 sulphide is approximately #j4a mol>1 & ! conc5tration ( hydrosulphide-ion1 !re=e1 9 ! abs5ce ( any =eign acid1 at mo/#cif #j4ie;,e#d4 ,! conc5tration ( ! dissolv$1 nonioniz$ hydrog5 sulphide1 ,h#b,s1 is practically a con/ant1 if solutions saturat$ ) hydrog5 sulphide "u a giv5 pressure1 say "u atmosph]ic pressure1 are consid]$4 ,= su* solutions1 !n1 we may put m simply#cif ,h ,,hs k 7#j4ie;,e#d7b #j4i;,e#h4 7,,ii7 ,! conc5tration ( hydrosulphide-ion is1 !re=e1 inv]sely proportional to ! conc5tration ( hydrog5-ion4 ,x is cle> t ! addition ( a /rong acid1 readily yield+ conc5trations ( hydrog5-ion v mu* great] ?an #j4ie;,e#d 7! value ( ,h 9 a saturat$ aque\s solution ( hydrog5 sulphide7 w1 z ! result ( ! greatly increas$ total hydrog5-ion conc5tration1 r$uce ! conc5tration ( hydrosulphide-ion to correspond+ly l[ values4 ,= in/ance1 ! pres5ce ( #j4a mol> hydro*loric acid w increase ! conc5tration ( hydrog5-ion close to a ?\s&fold & w r$uce ! conc5tration ( hydrosulphide-ion to #j4i;,e#g4 ,= ! second>y ionization 7see p4 #aja7 ( hydrog5 sulphide1 ,,hs ,h ,s#b1 we h ,h ,s#b _/ ,,hs ,k#b4 7,,iii7 ,! value ( ?is con/ant has rec5tly be5 det]m9$#cig & f\nd to be #a4b;,e#ae4 ,recall+ ! fact t ! conc5trations ,h & ,,hs ( hydrog5-ion & hydrosulphide-ion1 p#bja respectively1 result+ f ! prim>y ionization1 are ea*#cih #j4ie;,e#d1 we h = ! conc5tration ( ! sulphide-ion1 9 aque\s solution saturat$ ) hydrog5 sulphide at atmosph]ic pressure & #be1 ,s#b #a4b;,e#ae4 ,comb9+ equations 7,,ii7 & 7,,iii71 we h1 fur!r3#cii ,h#b ,s#b k ,k#b k#b #a4a;,e#bc1 7,,iv7 :i* %[s1 directly1 ! relation betwe5 ! conc5tration ( ! sulphide-ion & t ( ! hydrog5-ion1 ! relation ( prim>y importance 9 consid]+ ! precipitation ( metal sulphides 9 acid solutions4 ,! conc5tration ( ! sulphide-ion is1 ?us1 inv]sely proportional to ! squ>e ( ! conc5tration ( ! hydrog5-ion4 ,a ?\s&fold increase 9 ! conc5tration ( ! latt]1 :i* is v ne>ly ! effect produc$ by ! pres5ce ( #j4a mol> hydro*loric acid 7,h #j4jia71 r$uces ! conc5tration ( sulphide-ion 9 ! saturat$ aque\s solution a millionfold3 ,if we call ,s#b;,ac4 ! conc5tration ( ! sulphide-ion 9 ! acid solution1 ,s#b;,ac4 7#a4a;,e#bc7 _/ 7#j4jia7b #a4c;,e#ba1 :]eas1 9 ! abs5ce ( acid1 z f\nd above1 ,s#b #a4b;,e#ae4 ,on ! o!r h&1 ! addition ( alkali to hydrog5 sulphide1 by neutraliz+ & suppress+ ! hydrog5-ion1 & by =m+ ! salts ,me,s,h & ,me#b,s1 w v greatly increase ! conc5trations ( ! hydrosulphide-ion & ( ! sulphide-ion4 ,s9ce ! con/ant = ! second>y ionization ( hydrog5 sulphide %[s t ,,hs is an exce$+ly weak acid1 its salts1 ,me#b,s1 are v l>gely hydrolyz$1 ! con/ant = wat] be+ some:at great]#djj ?an its own4 ,accord+ to ,knox1 9 a #j4a mol> solution ( ,na#b,s ab\t #ii ( ! sulphide is hydrolyz$3 ,na#b,s ,h#b,o ,na,s,h ,na,o,h4 ,9 spite ( ?is almo/ complete hydrolysis1 suffici5t sodium sulphide rema9s 9 a solution ( ?is p#bjb sub/ance1 to yield a conc5tration ( ! sulphide-ion t is f> great] ?an t obta9$ f a solution ( hydrog5 sulphide4 ,9 a #j4a mol> solution ( sodium sulphide ! conc5tration ( ! sulphide-ion is1 approximately1 ,s#b;alk4 #j4i;,e#c1 z comp>$ ) ,s#b #a4b;,e#ae 9 a saturat$ solution ( hydrog5 sulphide 7#be1 #gfj mm471 & ) #a4c;,e#ba 9 ! same solution 9 ! pres5ce ( #j4a mol> hydro*loric acid4 ,ammonium sulphide 7,,nh#d7b,s is ! salt ( an extremely weak acid ) a mu* weak] base ?an sodium hydroxide1 & x is correspond+ly m completely decompos$ by wat]4 ,9 a #j4a mol> solution ( ! sulphide 7,,nh#d7b,s1 we f9d ! approximate conc5tration#dja ( ! sulphide-ion ,s#b;am4 #a4h;,e#f1 z comp>$ ) #j4i;,e#c 9 a simil> solution ( ,na#b,s4 ,b ! conc5tration ( sulphide-ion is /ill enorm\sly great] ?an its conc5trations 9 hydrog5 sulphide 9 ! abs5ce & 9 ! pres5ce ( acids 7see above74 ,! foll[+ table#djb conta9s a summ>y ( ! conc5trations ( sulphide-ion 9 ! v>i\s solutions discuss$1 z well z its conc5tration 9 ! pres5ce ( #j4b mol> hydro*loric acid4 ,9 ! sep>ation ( ! copp] & ars5ic gr\ps f ! z9c & alum9ium gr\ps1 a conc5tration ( hydrog5-ion correspond+ to ! pres5ce ( #j4ae to #j4be mol> hydro*loric acid is satisfactory = an accurate sep>ation = ord9>y purposes4 ,solution4 ,s#b #j4a mol> ,na#b,s3 #j4i;,e#c #j4a mol> ,na,s,h3 #j4h;,e#e #j4a mol> 7,,nh#d7b,s3 #a4h;,e#f #j4a mol> 7,,nh#d7,,%3 #a4d;,e#h #j4a mol> ,h#b,s1 sat4 aq4 sol41 #be3 #a4b;,e#ae #j4a mol> ,h#b,s1 #j4a mol> ,h,cl3#djc #a4c;,e#ba #j4a mol> ,h#b,s1 #j4b mol> ,h,cl3 #c4e;,e#bb p#bjc ,precipitation ( ,sulphides by ,hydrog5 ,sulphide4--,al?\gh ! hydrosulphide-ion mo/ likely takes "p 9 ! precipitation ( sulphides1 ! ma9 effect appe>s to be due to ! sulphide-ion4#djd ,! sulphides seem to be bo? m /able & less soluble1 ?an ! hydrosulphides4 ,x is v likely t hydrosulphides1 mix$ ) ! sulphides1 are precipitat$ to a c]ta9 ext5t1 b !y are un/able1 lose hydrog5 sulphide & g ov] into sulphides mu* m readily ?an hydroxides1 z a rule1 *ange into oxides4#dje ,! f9al condition ( equilibrium1 if "o wait$1 9 a giv5 case1 until equilibrium 0 e/abli%$1 w\ld dep5d1 "u ^! conditions1 r on ! conc5tration ( ! sulphide-ion ?an on t ( ! hydrosulphide-ion1 al?\gh ! latt] is pres5t 9 mu* great] conc5trations ?an ! =m]4 ,= ! sake ( simplify+ ! discussion ( ! !ory ( ! sep>ation ( metal ions by precipitation ) hydrog5 sulphide1 ! discussion w be limit$ to ! consid]ation ( ! sulphide-ion z ! active precipitat+ ag5t4 ,z /at$1 ?is seems to be 9 accordance ) ! kn[n facts4 ,! absolute values ( ! solubilities ( ! v>i\s sulphides1 :i* are involv$ 9 ! discussion1 are kn[n1 ) any degree ( accuracy1 only 9 a few cases4 ,! aim ( ! discussion w be1 !re=e1 to develop1 r1 ! relations 9 ! values involv$1 :i* may be readily det]m9$4 ,:]ev] absolute quantities c be giv51 !y also w be ref]r$ to4 ,!ory ( ! ,sep>ation ( ,sulphides by ,precipitation ) ,hydrog5 ,sulphide4 ,i4 ,precipitation ( ,f]r\s ,sulphide4--,if we prep>e a solution ( f]r\s sulphate1 conta9+ #bg4h grams ( ! salt1 ,fe,s,o#d1 #g ,h#b,o1 9 "o lit] 7#j4a mol>71 we may call ,fe#b ! conc5tration ( ! f]r\s-ion 9 ! solution4 ,if su* a solution is saturat$ ) hydrog5 sulphide1 "u atmosph]ic pressure1 7exp471 f]r\s sulphide is n precipitat$4 ,we w\ld decide1 on ! basis ( ! pr9ciple ( ! solubility-product1 t ! reason no precipitate ( f]r\s sulphide is =m$ is1 t ! product ( ! ion conc5trations is small] ?an ! p#bjd solubility-product con/ant *>act]i/ic ( ! sulphide 7p4 #aea72 ,fe#b ,s#b ,k,fe,s1 9 :i* ,s#b is ! conc5tration ( sulphide-ion 9 ! solution ?us saturat$ ) hydrog5 sulphide4 ,if an alkali1 sodium or ammonium hydroxide1 is add$ to ! solution1 a heavy precipitate ( f]r\s sulphide is imm$iately =m$ 7exp474 ,! salts ( hydrog5 sulphide1 l all common salts1 z we h j se51 are v mu* m highly ioniz$ ?an is hydrog5 sulphide itself1 & ! addition ( ! alkali has ! effect ( increas+ enorm\sly#djf ! conc5tration ( sulphide-ion1 say to x,s#b 7p4 #bjb74 ,"u ^! conditions1 ! product ( ! ion conc5trations has evid5tly gr[n l>g] ?an ! con/ant3 ,fe#b x,s#b ,k,fe,s4 ,,ii4 ,precipitation ( ,z9c ,sulphide4--,n[1 if a solution ( z9c sulphate is prep>$ s z to conta9 #bh4g grams ( ,zn,s,o#d1 #g ,h#b,o1 p] lit]1 :i* w\ld make x ( ! same mol> conc5tration z ! f]r\s sulphate solution1 we may1 9 view ( ! fact t analog\s salts ionize approximately to ! same ext5t 9 solutions ( ! same conc5tration1 consid] ! conc5tration1 ,zn#b1 ( z9c-ion to be practically ! same z ! conc5tration1 ,fe#b1 ( ! f]r\s-ion 9 ! f]r\s sulphate solution4 ,we may put ,zn#b ,fe#b4 ,if ! solution ( z9c sulphate is saturat$ ) hydrog5 sulphide1 "u ! same conditions z 7 us$ ) ! f]r\s salt solution 7exp471 or if we add ! z9c sulphate solution to ! mixture ( f]r\s sulphate & hydrog5 sulphide 7exp471 we imm$iately obta9 heavy :ite precipitates ( z9c sulphide4 ,we w\ld decide1 !re=e1 on ! basis ( ! pr9ciple ( ! solubility-product1 t 9 ?is case ,zn#b ,s#b ,k,zn,s4 ,s9ce we h us$ hydrog5 sulphide "u practically ! same conditions1 we may consid] t ,s#b1 9 ?is exp]im5t1#djg is ! same z 9 ! p#bje te/ ) f]r\s sulphate1 &1 by ! conditions ( ! exp]im5t1 we h also made ,zn#b ,fe#b4 ,! two factors ( ! product are1 !re=e1 ! same1 = ! fir/ mom5t1 & we may put ,fe#b ,s#b ,zn#b ,s#b ,p4 ,s9ce ,p is small] ?an ,k,fe,s & l>g] ?an ,k,zn,s1 x is cle> t ! solubility-product con/ant = z9c sulphide mu/ be small] ?an t = f]r\s sulphide4 ,! solubility-product con/ants1 = simil> salts1 are a measure ( _! solubilities 9 wat]4 ,we may obta9 _! values by det]m9+ ! solubilities ( salts 9 pure wat]1 :5ev] ! solubility is n affect$ by o!r *emical *anges4 ,9 ! pres5t in/ance1 ! quantitative measurem5ts1 t h be5 made 9 ?is way1 are op5 to "q1 ow+ to ! consid]able hydrolysis :i* sulphides1 z salts ( a v weak acid1 und]go 9 solutions ( su* extreme dilution4#djh ,until su* relations h be5 tak5 into acc\nt quantitatively1 x is bett] to limit ourselves = ! pres5t to ! m accessible "q ( relative solubility4 ,x is a comp>atively easy matt] to det]m9e ! relative solubility ( z9c & f]r\s sulphides4 ,if equal quantities ( ! equival5t solutions are mix$ & a precipitant1 ammonium sulphide1 :i* w\ld precipitate ei!r sulphide1 if its salt 7 pres5t alone1 is c>efully & gradually add$ to ! mixture1 x w precipitate fir/ ! less soluble "o 7see p4 #afc72 & t "o alone c be pres5t p]man5tly 7i4e4 9 equilibrium7 9 contact ) ! solution conta9+ ! two salts4 ,z a matt] ( fact1#dji p#bjf we f9d t z9c sulphide is precipitat$ fir/1 "u conditions p]mitt+ ! precipitation ( f]r\s sulphide if no z9c sulphate 7 pres5t1 & ! precipitate ( z9c sulphide rema9s un*ang$ 9 ! pres5ce ( a mixture ( ! composition indicat$ 7exp474 ,x is cle>1 !re=e1 t ! pr$iction1 bas$ on ! conclusion drawn f ! application ( ! pr9ciple ( ! solubility-product1 is v]ifi$ by exp]im5t4 ,n[1 clos] exam9ation ( ! solution ( z9c sulphate1 f :i* z9c sulphide has be5 precipitat$ by ! action ( hydrog5 sulphide1 %[s1 aft] ! hydrog5 sulphide has precipitat$ z mu* sulphide z x c & ! solution has be5 pass$ ?r\gh a filt]1 t a v consid]able proportion ( z9c salt is /ill pres5t 9 ! filtrate1 & we mu/ ask :y hydrog5 sulphide fails to precipitate ! z9c completely4 ,! conc5tration ( ! z9c-ion has gr[n some:at small]1 b t is n ! cause ( ! nonprecipitation ( z9c sulphide "u ! new conditions1 s9ce hydrog5 sulphide w precipitate ! sulphide1 if x is pass$ into a solution ( z9c sulphate :i* conta9s ev5 a small] conc5tration ( z9c-ion ?an ! filtrate1 9 :i* x fails to give any fur!r precipitate4 ,if ! filtrate is exam9$1 x is f\nd to be /rongly acid1 s9ce sulphuric acid has be5 lib]at$ by ! action ( hydrog5 sulphide on z9c sulphate3 ,zn,s,o#d ,h#b,s ,zn,s ,h#b,,s#d4 ,sulphuric acid is a /rong acid1 :i* is v highly ioniz$1 mu* m s ?an ! exce$+ly weak acid hydrog5 sulphide1 & consequ5tly1 z ! precipitation ( z9c sulphide proce$s1 ! conc5tration ( hydrog5-ion 9 ! solution rapidly gr[s l>g] & l>g]4 ,b1 ! great] ! conc5tration ( ! hydrog5-ion1 ! small] is t ( ! sulphide-ion1 s9ce ! product ,h#b ,s#b is a con/ant equation 7,,iv71 p4 #bja = a solution kept saturat$ ) hydrog5 sulphide4 ,! sulphide-ion is r$uc$ 9 conc5tration v mu* m rapidly ?an is ! z9c-ion4#daj ,z ,s#b is a factor 9 ! p#bjg solubility-product ( z9c sulphide1 x is cle> t ! value ( ?is product mu/ gr[ rapidly small] dur+ ! precipitation ( z9c sulphide f ! solution1 & t x may well1 ev5tually1 gr[ too small to surpass ! value ( ! solubility-product con/ant ,k,zn,s4 ,precipitation ( z9c sulphide w !n cease4 ,obvi\sly1 ! suppression ( ! sulphide-ion may be accompli%$ by ! addition ( hydro*loric1 sulphuric or any o!r /rong acid to ! z9c sulphate solution 9 ! fir/ place1 & !n hydrog5 sulphide %\ld fail to precipitate any z9c sulphide at all4 ,9 fact1 if to #ej c4c4 ( ! #j4a mol> z9c sulphate solution #b c4c4 ( hexamol> hydro*loric acid is add$1#daa hydrog5 sulphide does n precipitate ev5 a trace ( z9c sulphide 7exp474 ,we h f\nd1 !n1 t #j4a mol> z9c sulphate solution1 acidifi$ ) a small excess ( hydro*loric acid1 fails to produce a precipitate ( z9c sulphide1 :5 x is saturat$ ) hydrog5 sulphide4 ,we mu/ conclude t1 "u ^! circum/ances1 ! product ( ! ion conc5trations is small] ?an ! solubility-product con/ant = z9c sulphide3 7,zn#b ,s#b _/ x7 ,k,zn,s1 ! new conc5tration ( ! sulphide-ion be+ repres5t$ by ! symbol ,s#b _/ x4 ,x w\ld foll[1 f ^! consid]ations1 t ! action ( hydro*loric or sulphuric acid1 9 prev5t+ ! precipitation ( z9c sulphide1 dep5ds on _! produc+ a suffici5tly high conc5tration ( ! hydrog5-ion1 to keep ! conc5tration ( ! sulphide-ion1 9 a mixture ( z9c sulphate & hydrog5 sulphide1 bel[ ! po9t :]e ! solution c\ld become sup]saturat$ ) z9c sulphide4 p#bjh ,= exactly simil> reasons1 none ( ! sulphides ( ! z9c gr\p is precipitat$ by hydrog5 sulphide 9 7suffici5tly7 acid solutions4 ,x is evid5t1 fur!r1 t1 if a solution ( z9c acetate 7)\t ! addition ( any acid7 is sub/itut$ = ! z9c sulphate solution & is treat$ ) hydrog5 sulphide1 an entirely diff]5t result1 quantitatively consid]$1 mu/ be obta9$4 ,by ! action ( hydrog5 sulphide on ! acetate1 acetic acid is lib]at$1 accord+ to ,zn7,,*#c;,,co#b7b ,h#b,s ,zn,s #b ,,*#c;,,cooh4 ,z a weak acid1 acetic acid produces mu* less hydrog5-ion ?an is =m$ 9 equival5t solutions ( sulphuric acid4 ,consequ5tly1 a mu* slight] suppression ( ! sulphide-ion & a mu* m complete precipitation ( z9c sulphide f ! acetate1 ?an f ! sulphate solution1 mu/ result4 ,su* is ! case4 ,z9c sulphide is1 inde$1 precipitat$ quantitatively by hydrog5 sulphide f ! acetate solution4 ,?is behavior ( z9c acetate#dab--;& z9c salts ( o!r weak acids %[1 ( c\rse1 ! same behavior--repres5ts "o ( ! pitfalls1 into :i* ! unw>y analytical *emi/ is liable to fall1 :5 he uses hydrog5 sulphide4 ,! sep>ation ( gr\ps by hydrog5 sulphide dep5ds1 z /at$1 on ! fact1 t1 9 ! pres5ce ( a c]ta9 conc5tration ( hydrog5-ion1 hydrog5 sulphide w n precipitate z9c sulphide & ! rema9+ sulphides ( ! z9c gr\p4 ,to secure ?is conc5tration ( hydrog5-ion1 "s hydro*loric acid is add$ to solutions1 f :i* hydrog5 sulphide is expect$ to precipitate none b sulphides ( ! copp] & ars5ic gr\ps--&1 z a rule1 ! purpose is accompli%$1 z desir$4 ,x is evid5t1 h[ev]1 t if a solution conta9s an acetate1 say sodium acetate1 or ! salt ( any o!r weak acid1 e4g4 a borate or a phosphate1 ! addition ( hydro*loric acid w result1 at lea/ at fir/1 9 ! lib]ation ( ! weak] acid & w n produce ! excess ( hydrog5-ion1 requir$ = ! analysis4 ,z9c sulphide1 & possibly nickel & cobalt sulphides1#dab may1 "u su* conditions1 be precipitat$ ) ! sulphides ( ! gr\ps m5tion$4 ,unless provision is made1 !re=e1 to insure a c]ta9 excess ( hydrog5-ion 7p4 #bac71 or unless we are on our gu>d & look = z9c1 nickel & cobalt 9 p#bji ! analysis ( ! precipitate =m$ by hydrog5 sulphide1#dac s]i\s errors obvi\sly c\ld result4 ,to add an inord9ately l>ge excess ( hydro*loric acid to mixtures1 9 ord] to avoid ?is pitfall1 w1 z we %all pres5tly see1 only ?r[ u m c]ta9ly into /ill ano!r error1 to :i* we are expos$ 9 ! use ( ?is important reag5t1 hydrog5 sulphide4 ,,iii4 ,precipitation ( ,cadmium ,sulphide4--,n[1 if a #j4a mol> solution ( cadmium sulphate 7#bb4f grams ( ! salt1#dad ,cd,s,o#d1 ,h#b,o1 p] lit]7 is prep>$1 equival5t1 9 conc5tration1 to ! solutions ( f]r\s & z9c sulphates us$ previ\sly1 we may consid] t ! conc5tration ( cadmium-ion is1 approximately1 ! same z ! conc5trations ( ! f]r\s-ion & z9c-ion 9 ! solutions ( _! sulphates4 ,if ! solution ( cadmium sulphate is add$ to ! acidifi$ solution ( z9c sulphate1 :i* 0 saturat$ ) hydrog5 sulphide b f :i* no z9c sulphide c\ld be precipitat$ 7exp41 p4 #bjg71 a heavy precipitate ( cadmium sulphide is at once obta9$ 7exp474 ,or1 if #b c4c4 ( hexamol> hydro*loric acid is add$ to #ej c4c4 ( ! cadmium sulphate solution & ! mixture is saturat$ ) hydrog5 sulphide1#dae cadmium sulphide is precipitat$ readily 7exp47 &1 9 fact1 quantitatively4 ,we w\ld decide1 on ! basis ( ! pr9ciple ( ! solubility-product1 t1 9 ?is mixture1 precipitation results because 7,cd#b ,s#b _/ x7 ,k,cd,s4 ,by ! conditions ( ! exp]im5t we />t$ ) a conc5tration ( ! cadmium-ion1 ,cd#b1 equal to ! conc5tration1 ,zn#b1 ( ! z9c-ion 9 ! z9c sulphate solution1 & ) ! same conc5tration1#dae ,s#b _/ x1 ( sulphide-ion z 0 us$ :5 hydrog5 sulphide fail$ to precipitate z9c sulphide4 ,! correspond+ factors ( ! products ( ! ion conc5trations are equal1 at ! beg9n+ ( ! two exp]im5ts1 & we may put 7,cd#b ,s#b _/ x7 7,zn#b ,s#b _/ x7 ,p4 ,we recall ! fact1 t we h already conclud$1 on ! basis ( ! pr9ciple ( ! solubility-product1 t 7,zn#b ,s#b _/ x71 or ,p1 is small] ?an ,k,zn,s 7p4 #bjg71 & t 7,cd#b ,s#b _/ x71 or ,p1 is great] ?an ,k,cd,s4 ,p be+ small] ?an ,k,zn,s & l>g] ?an ,k,cd,s1 x is cle> t p#baj ,k,cd,s is small] ?an ,k,zn,s & t cadmium sulphide mu/ be ! less soluble ( ! two sulphides4 ,z a matt] ( fact1 if ammonium sulphide is c>efully add$ to a mixture ( equal quantities ( ! two salt solutions1 cadmium sulphide is precipitat$ fir/1 & :5 practically all ( ! cadmium is precipitat$1 a f9al precipitate ( :ite z9c sulphide is obta9$ 7exp42 see note1 p4 #bje74 ,or1 if z9c sulphide is fir/ precipitat$ by ! addition ( a little ammonium sulphide to #be c4c4 ( ! #j4a mol> z9c sulphate solution1 c>e be+ tak5 to h z9c sulphate 9 excess1 & if #be c4c4 ( ! #j4a mol> cadmium sulphate solution is !n add$ to ! mixture1 ! :ite z9c sulphide imm$iately gives way to ! less soluble yell[ cadmium sulphide 7exp42 see p4 #afe74 ,cadmium sulphide is ?us prov$ to be ! less soluble ( ! two sulphides1 a result :i* confirms ! pr$iction made above ) ! aid ( ! pr9ciple ( ! solubility-product1 & we may inde$ conclude t ! solubility-product con/ant ,k,cd,s ( cadmium sulphide mu/ be small] ?an ! con/ant ,k,zn,s ( z9c sulphide 7see pp4 #afc-afh1 on fractional precipitation74 ,we are1 !re=e1 also ju/ifi$ 9 decid+ t ,cd,s may well be precipitat$ f acidulat$ solutions by hydrog5 sulphide1 :5 ,zn,s is n ?us precipitat$1 simply because ,k,cd,s is suffici5tly small 7,cd,s is suffici5tly insoluble7 to make ! product ( ! ion conc5trations ,cd#b ,s#b _/ x1 9 spite ( ! extremely small value ( ,s#b _/ x1 great] ?an ! con/ant ,k,cd,s1 :]eas ! same small value ( ,s#b _/ x makes x impossible = ! product ,zn#b ,s#b _/ x to rea* ! value ( ! l>g] con/ant ,k,zn,s1 requir$ = ! precipitation ( ,zn,s4 ,s9ce cadmium sulphide may be precipitat$ quantitatively "u ! conditions giv51 x is also evid5t t x may be precipitat$ ev5 :5 ! conc5tration ( ! cadmium-ion also has a r small value4 ,! relations1 9 reg>d to ?is po9t1 w be discuss$ pres5tly4 ,! ,sep>ation ( ! ,copp] & ,ars5ic ,gr\ps f ! ,z9c ,gr\p4--,f]r\s-ion & z9c-ion may be tak5 z typical repres5tatives ( ! ions ( ! z9c gr\p1 ^: sulphides are n precipitat$ by hydrog5 sulphide 9 ! pres5ce ( a def9ite conc5tration ( hydrog5-ion1 cadmium-ion z a repres5tative ( ! copp]1 silv] & ars5ic gr\ps1 ^: sulphides are precipitat$ "u ! same conditions4 ,! sep>ation ( ! gr\ps dep5ds1 !re=e1 on ! diff]5t solubilities ( ! sulphides ( ^! p#baa gr\ps1 ! sulphides ( ! z9c gr\p be+ ! mo/ soluble4 ,s9ce ev5 ^! sulphides are precipitat$ quantitatively by ammonium sulphide & are v difficultly soluble1 ! sep>ation is a k9d ( fractional precipitation ( difficultly soluble salts1 9 :i* ! fractionation is made possible & conv5i5t by ! use ( an ag5t1 hydrog5 sulphide1 ! conc5tration ( ^: active precipitat+ compon5t1 ! sulphide-ion1 ,s#b1 is easily regulat$ & readily made suffici5tly small1 n to precipitate ev5 ! difficultly soluble sulphides ( ! iron gr\p4 ,solubilities v>y f salt to salt1 & we h already f\nd t1 9 ! z9c gr\p1 z9c sulphide is less soluble ?an ! sulphide ( a second memb] ( ! gr\p1 f]r\s sulphide1 & t ! diff]5ce is reveal$ 9 a some:at diff]5t behavior ( _! salts t[>d hydrog5 sulphide1 :5 ! action is /udi$ 9 "s detail4 ,simil> diff]5ces mu/ be expect$ to exi/ among ! sulphides ( ! gr\ps t hydrog5 sulphide precipitates ev5 9 ! pres5ce ( an excess ( hydro*loric acid4 ,z ^! diff]5ces are ! s\rces ( "s ( ! mo/ common & mo/ s]i\s errors :i* analy/s are liable to commit1 ! detail$ /udy ( ! action ( hydrog5 sulphide mu/ be cont9u$ a little fur!r4 ,! ,effect ( a ,l>ge ,excess ( ,acid4--,! precipitation ( cadmium sulphide dep5ds on ! relation ( ! product ( ! conc5trations ( ! cadmium-ion & ! sulphide-ion to ! solubility-product con/ant = cadmium sulphide 7see ! equation1 p4 #bji74 ,n[1 x is cle> t if a l>g] & l>g] excess ( hydrog5-ion is introduc$ by ! addition ( m conc5trat$ hydro*loric acid to ! cadmium sulphate solution1 ! conc5tration ( sulphide-ion is correspond+ly r$uc$4#daf ,! po9t might be rea*$1 :]e ! sulphide-ion factor becomes s small1 t ! product ( ! ion conc5trations rema9s small] ?an ! value ,k,cd,s1 requir$ = precipitation ( cadmium sulphide4 ,9 fact1 if a l>ge excess#dag ( hydro*loric acid is add$ to #ej c4c4 p#bab ( ! #j4a mol> solution ( cadmium sulphate1 hydrog5 sulphide fails to precipitate any ( ! sulphide 7exp474 ,b1 if a few cubic c5timet]s ( a #j4a mol> solution ( cupric sulphate 7#be4j grams ( ,cu,s,o#d1 #e ,h#b,o1 p] lit]7 are add$ to ! solution f :i* hydrog5 sulphide fails to precipitate cadmium sulphide1 cupric sulphide is at once precipitat$4 ,&1 if #ae c4c4 ( conc5trat$ hydro*loric acid are add$ to #ej c4c4 ( ! #j4a mol> cupric sulphate solution1 !re results a mixture correspond+ to ! cadmium sulphate solution f :i* hydrog5 sulphide fails to precipitate ,cd,s2 we f9d t hydrog5 sulphide w precipitate ! sulphide ( copp] v readily1 ev5 "u ^! adv]se conditions 7exp474 ,cupric sulphide mu/ be ev5 less soluble 9 wat] ?an cadmium sulphide1#dah & !re is no difficulty 9 %[+ t su* is ! case4 ,if ammonium sulphide1 or hydrog5 sulphide1 is gradually introduc$ into a mixture ( #be c4c4 ea* ( ! #j4a mol> sulphate solutions1 cupric sulphide is precipitat$ fir/1 &1 if ! precipitate is collect$ 9 fractions1 p#bac pure yell[ cadmium sulphide is precipitat$ la/4#dai ,or1 if #be c4c4 ( #j4a mol> cupric sulphate is add$ to ! mixture 9 :i* a precipitate ( cadmium sulphide displac$ ! m soluble z9c sulphide 7p4 #baj71 ! yell[ sulphide w1 9 turn1 give way to ! less soluble black sulphide ( copp] 7exp474 ,we f9d ?us t ! precipitation ( cadmium sulphide1 by hydrog5 sulphide 9 acid solution1 c be prev5t$ by ! pres5ce ( an excess ( hydro*loric acid1 :i* does n prev5t ! precipitation ( ! less soluble cupric sulphide4#dbj ,! fact1 !n1 t1 9 an analysis ( "s unkn[n mixture1 hydrog5 sulphide produces a precipitate 9 acid solution1 mu/ n be consid]$ z evid5ce t ! conditions are su* z to insure ! precipitation ( all ! sulphides ( ! gr\ps1 :i* we int5d to precipitate4 ,to avoid error1 conditions mu/ be su* z to insure ! complete precipitation ( ! m soluble z well z ! less soluble sulphides4 ,! sulphides ( cadmium & lead1 9 p>ticul>1 &1 to a less] degree1 ! sulphides ( antimony & t91 are mo/ liable to rema9 unprecipitat$ & ?us escape detection 9 sy/ematic analysis4 ,?is is a matt] ( special importance1 also1 9 detect+ traces ( ! ions ( ^! metals1 especially ( lead1 :i* is a sl[ cumulative poison1 ev5 :5 absorb$ 9 m9ute am\nts1 & :i* analy/s mu/ !re=e be able to detect1 ev5 9 traces1 ) absolute c]ta9ty4 ,x is cle>1 f a consid]ation ( ! product ( ! ion conc5trations1 z affect+ ! precipitation or nonprecipitation ( su* a sulphide1 t a mu* small] excess ( acid w prev5t ! precipitation ( ! la/ traces ( lead sulphide1 &1 !re=e1 ( all ( x1 if only traces are pres5t1 ?an w int]f]e ) ! precipitation ( ! sulphide 9 bulk4 ,! ,desirable ,conc5tration ( ,acid 7( ,hydrog5-ion7 & an ,indicator = ,correct ,acidification4--,summ>iz+ ! conclusions rea*$ 9 reg>d to ! conditions necess>y = a successful sep>ation ( ! copp] & ars5ic gr\ps1 by means ( hydrog5 sulphide1 f ! z9c & alum9ium gr\ps1 we f9d p#bad t ! conc5tration ( ! hydrog5-ion1 9 ! solution to be treat$ ) hydrog5 sulphide1 is ! mo/ important factor4 ,too great a conc5tration1 z has j be5 %[n1 w prev5t ! precipitation ( all1 or "p1 ( ! m soluble sulphides ( ! =m] gr\ps1 notably ( ! sulphides ( cadmium & lead1 :i* is a common error 9 ! laboratory4 ,too small a conc5tration1 :i* may result :5 a salt ( a weak acid1 su* z an acetate1 borate or phosphate is pres5t1 may lead1 z 0 %[n above1 to ! precipitation ( "p ( ! z9c gr\p1 notably ( z9c & possibly ( nickel & cobalt1 ) ! copp] & ars5ic gr\ps1 & ?us lead to o!r errors4 ,= ! ord9>y purposes ( analysis1 requir+ ! precipitation ( say "o milligram ( any ion f #ajj c4c4 solution 7"o-t5? p] c5t1 if "o gram ( sub/ance is us$ = analysis71 a conc5tration ( hydrog5-ion ( #j4a to #j4c gram-ion p] lit] =ms a good basis = "w4#dba ,! pres5ce ( ?is conc5tration ( hydrog5-ion1 irrespective ( ! possible pres5ce ( weak organic or inorganic acids1 may be readily insur$ by a simple te/ ) an appropriate indicator4 ,me?yl-violet#dbb is suitable = su* a purpose1 because x is s5sitive only to ! r high conc5trations ( hydrog5-ion requir$3 #j4a c4c4 or two drops ( #j4je to #j4a mol> hydro*loric acid1 add$ to an equal volume ( a v dilute solution 7#a 3 #ab1ejj7 ( ! indicator1 *anges its color to a pure blue2 #j4b to #j4be mol> acid1 us$ simil>ly1 turns ! indicator to a blue-gre5 t9t1 & #j4cc mol> acid produces a yell[ or yell[-gre5 hue4 ,! blue-gre5 t9t1 ) :i* "o becomes easily famili>1 & :i* c1 inde$1 always be prep>$ = mat*+ t9ts1 may be us$ to recognize spe$ily1 & ) suffici5t accuracy1 a conc5tration ( ! hydrog5-ion ( ! /r5g? desir$1 irrespective ( its s\rce4#dbc ,if an analy/ aims to f9d ev5 small] quantities ( a p>ticul> metal ion1 e4g4 traces ( lead1 ! ord9>y me?od ( analysis p#bae may be modifi$1 ! s\rce ( error 9 ! precipitation ( traces ( lead sulphide be+ kept 9 m9d4#dbd ,besides ! complications m5tion$1 & provid$ aga9/ 9 ! way discuss$1 !re is /ill "o m complication 9 ! use ( hydrog5 sulphide3 ?is is 9 ! matt] ( ! precipitation ( ars5ic sulphide f solutions conta9+ ars5ic 9 ! p5taval5t condition4 ,s9ce ! int]pretation ( ?is complication & ! explanation ( ! me?ods = avoid+ ! errors1 :i* may arise !refrom1 are necess>ily intimately connect$ ) ! *emical behavior ( ars5ic acid1 ?is subject w be consid]$ 9 ! discussion ( ! ars5ic gr\p 7,*apt] ,,xiii74 ,,footnotes3 #cie ,au]ba*1 ,z4 phys4 ,*em41 #di1 #bbj 7#aijd74 #cif ,see footnote #a1 p4 #bja4 #cig ,knox 79 ,abegg's laboratory71 ,trans4 ,f>aday ,soc41 #d1 #dd 7#aijh74 #cih ,! conc5tration ( ! hydrog5-ion is really a little great] ?an t ( ! hydrosulphide-ion1 z a result ( ! ionization ( ! latt]1 b ! am\nt ( hydrog5-ion =m$ 9 ?is way 7ab\t #a;,e#ae7 is s m9ute1 comp>$ ) t =m$ by ! prim>y ionization1 t x is negligible4 #cii ,we c obta9 ! relation1 directly1 f ,h#b,s #b ,h ,s#b & ,h#b ,s#b _/ ,h#b,s ,k #a4a;,e#bb4 ,= a giv5 pressure ( ! hydrog5 sulphide1 ,h#b,s1 express+ its solubility 7ab\t #j4a mol> at #be71 is con/ant1 & !re=e ,h#b ,s#b a con/ant1 z giv5 9 equation 7,,iv74 ,putt+ ,h#b,s #j4a1 we h ,h#b ,s#b #j4a #a4a;,e#bb #a4a;,e#bc4 #djj ,on acc\nt ( ! great mass ( wat]1 we comp>e 7see equation1 p4 #agf7 ,h ,,ho #a4b;,e#ad 7at #be7 ) ,h ,s#b _/ ,,hs #a4b;,e#ae4 #dja ,! calculation 0 made by ! me?od us$ by ,knox 7loc4 cit47 = a mol> solution4 ,! degree ( ionization ( ! salt 0 n consid]$ & ! correct ionization con/ant = ammonium hydroxide 0 us$1 #a4h;,e#e 9 place ( #b4c;,e#e4 ,! latt]1 evid5tly1 0 us$ by ,knox z ! result ( ov]look+ a correction1 :i* ,br$ig made 9 8 7,br$ig's7 fir/ calculations ( ! con/ant2 cf4 ,br$ig1 ,z4 phys4 ,*em41 #ac1 #bic1 footnote4 ,! same errone\s con/ant is f\nd 9 ,kohlraus* & ,holborn1 loc4 cit41 p4 #aid4 #djb ,= fur!r values & = ! me?od ( calculation1 see ,knox1 loc4 cit4 #djc ,s#b #a4a;,e#bc _/ ,h#b1 accord+ to equation 7,,iv71 p4 #bja4 #djd ,knox's "w leads to t conclusion4 #dje ,! precipitation ( sulphides1 f a solution conta9+ mu* m ( ! hydrosulphide-ion ?an ( ! sulphide-ion1 is comp>able ) ! precipitation ( m]curic oxide1 ,hg,o1 & ( silv] oxide1 ,ag#b,o1 by sodium or potassium hydroxide4 #djf ,on acc\nt ( ! pres5ce ( a small1 unkn[n am\nt ( sulphuric acid 9 ! orig9al solution1 result+ f ! hydrolysis ( f]r\s sulphate1 ! exact value ( ,s#b 9 ! fir/ solution _c be calculat$ )\t fur!r exam9ation2 b1 accord+ to ! values giv5 9 ! table on page #bjb1 ! value ( x1 indicat+ ! gr[? 9 ! conc5tration ( ,s#b1 is at lea/ #ajab1 if #b equival5ts ( ,na,o,h1 & #aji1 if #b equival5ts ( ,,nh#d,,oh are us$ to conv]t ! #j4a mol> hydrog5 sulphide into ! correspond+ sulphide ,me#b,s1 ( #j4a mol> conc5tration4 #djg ,s#b is exactly ! same 9 ! two products1 :5 equal volumes ( ! z9c & f]r\s sulphate solutions are mix$ & ! mixture is saturat$ ) hydrog5 sulphide2 z9c sulphide is precipitat$4 #djh ,! diff]5ce 9 ! values obta9$1 :5 hydrolysis is consid]$ or neglect$1 is v consid]able4 ,vide ,bodlnd]1 on ! solubility ( calcium c>bonate1 ,z4 phys4 ,*em41 #ce1 #bc 7#aijj71 & ,/ieglitz1 ,c>negie ,in/itution ,publications1 ,no4 #ajg1 #bdi 7#aiji74 #dji ,9 c>ry+ out ?is fractional precipitation a v dilute solution ( ammonium sulphide is us$1 s z to prev5t ! me*anical enclosure ( black f]r\s sulphide1 :i* w\ld discolor ! :ite sulphide4 ,! ammonium sulphide solution %\ld be saturat$ ) hydrog5 sulphide1 to prev5t ! precipitation ( gre5 f]r\s-f]ric oxide by an excess ( free ammonia4 ,x is be/ to prep>e a set ( ! precipitates & to pres]ve !m 9 well-/opp]$ vessels1 & n to try to take ! "t & c>e necess>y to effect a p]fect fractionation z a lecture exp]im5t4 ,! pres5ce ( ! f]r\s sulphate1 9 ! sup]natant liquid above ! fir/ precipitate ( z9c sulphide1 may be readily demon/rat$ by p\r+ (f "s ( ! solution & add+ an excess ( ammonium sulphide to x4 ,( c\rse1 x is also p]fectly legitimate1 & easi]1 to precipitate fir/ z9c sulphide f a pure z9c sulphate solution & !n to add f]r\s sulphate solution to ! mixture & to pres]ve ! mixture4 ,if ! z9c sulphide 7 n ! less soluble1 x w\ld be rapidly conv]t$ into ! black f]r\s sulphide4 7,see p4 #afe1 & see bel[1 pp4 #baj1 #bac1 :]e simil> trans=mations are c>ri$ out z lecture exp]im5ts47 #daj ,:5 #aj ( ! z9c 9 a #j4a mol> solution has be5 precipitat$1 #j4ja mol> sulphuric acid has be5 =m$4 ,= ! sake ( a r\gh approximation1 ! acid may be consid]$ completely ioniz$ & !n ,h #j4jb1 :i* is #bjj times ! value ( ,h 9 a saturat$ ,h#b,s solution 7p4 #bjj72 if ! pres5ce ( a little sulphuric acid 9 ! orig9al z9c sulphate solution1 result+ f a slight hydrolysis ( ! salt1 is ignor$1 ! conc5tration ( ! sulphide-ion is decreas$ r\ghly 7#bjj7b or =ty ?\s&fold1 :ile ! conc5tration ( z9c-ion falls #aj4 ,! corrections1 t h be5 indicat$1 w\ld *ange ! quantities involv$1 b !y w\ld n modify ! "* ( ! result4 #daa ,?is proportion ( acid1 mak+ ! conc5tration ( ! hydrog5-ion1 approximately1 ,h #j4b1 is us$1 n because x repres5ts ! m9imum conc5tration ( ! hydrog5-ion1 :i* w prev5t ! precipitation ( z9c sulphide 9 #j4a mol> z9c sulphate solution1 b because x repres5ts ! practical conditions "u :i* ! precipitation ( z9c sulphide is avoid$1 :5 ! copp] & ars5ic gr\ps are precipitat$ 9 qualitative analysis 7see p4 #bac74 #dab ,nickel & cobalt sulphides are also precipitat$ by hydrog5 sulphide 9 ! pres5ce ( free acetic acid1 if sodium or potassium acetate is add$1 to suppress ! hydrog5-ion ( ! acetic acid 7p4 #aab74 #dac ,!y w\ld be f\nd 9 ! copp] gr\p4 #dad ,! sulphate1 ( ?is composition1 is obta9$ by dry+ ! cry/alliz$ sulphate 9 an air ba? at #ajj-aje4 #dae ,cf4 ! correspond+ exp]im5t ) z9c sulphate1 p4 #bjg4 #daf ,s#b k _/ ,h#b4 ,see equation 7,,iv71 p4 #bja4 #dag ,any imm$iate precipitation ( cadmium sulphide w be prev5t$ by ! addition ( #aj c4c4 ( conc5trat$ acid 7sp4 gr4 #a4ai7 to #ej c4c4 ( ! #j4a mol> solution1 & #ae c4c4 w completely prev5t any precipitation ( ! sulphide4 ,( c\rse1 a small] excess w\ld prev5t ! precipitation ( small quantities ( ! sulphide 7e4g4 a half milligram ( cadmium71 :i* %\ld easily be f\nd 9 #ej c4c4 7see p4 #bad74 #dah ,! value ( ! solubility-product con/ant = cupric sulphide1 at #be1 0 det]m9$ by ,knox 7loc4 cit473 ,cu#b ,s#b #a4b;,e#db1 correspond+ to a conc5tration ( #a4a;,e#ba ( cupric-ion4 ,m]curic sulphide 0 f\nd ev5 less soluble3 ,hg#b ,s#b #b4h;,e#ed1 & its behavior agrees ) su* a relation 7,lab4 ,manual1 p4 #ej1 #b74 ,! solubility-product con/ant = lead sulphide1 :i* resembles cadmium sulphide 9 ! fact t a l>ge excess ( acid prev5ts its precipitation1 0 f\nd to be ,pb#b ,s#b #b4f;,e#ae1 ! con/ant be+ ab\t #ajbg times z l>ge z ! con/ant = cupric sulphide4 ,?is value = ! solubility-product con/ant = lead sulphide mu/ ei!r be consid]ably l>g] ?an ! true value or lead mu/ be easily precipitat$ z a hydrosulphide1 ,pb7,,%7#b1 s9ce solutions 9 :i* ! product ( ! ion conc5trations1 ,pb#b ,s#b1 is v mu* small] ?an ! con/ant giv51 readily precipitate lead sulphide4 ,?us ,noyes & ,bray ,j4 ,am4 ,*em4 ,soc41 #bi1 #acg 7#aijg7 report x possible to precipitate #a to #b milligrams ( lead-ion 9 #ajj c4c4 ( solution 7say ,pb#b #a;,e#d7 ) hydrog5 sulphide 9 ! pres5ce ( #d c4c4 ( hydro*loric acid 7sp4 gr4 #a4ab71 = :i*1 approximately1 ,h #j4be4 ,!n 7equation 7,,iv71 p4 #bja7 ,s#b 7#a4a;,e#bc7 _/ 7#j4be7b #a4h;,e#bb1 & ,pb#b ,s#b #a;,e#d #a4h;,e#bb #a4h;,e#bf1 :i* is a mu* l[] value ?an t giv5 by ,knox1 & :i* /ill is n claim$ to repres5t ! limit ( insolubility4 ,exp]im5ts1 made 9 ?is laboratory1 confirm ?is result & %[ fur!r1 t lead-ion 9 a conc5tration ( #a;,e#e is precipitat$ 9 ! pres5ce ( #j4be mol> hydro*loric acid 7,h #j4bb74 ,!n ,s#b #b4c;,e#bb & ,pb#b ,s#b #b4c;,e#bb #aje #b;,e#bg1 :i* does n yet express ! limit ( insolubility4 #dai ,! fractions are n prep>$ 9 ! lecture1 b ! fir/ fraction is kept susp5d$ 9 "p ( ! solution ( ! two sulphates & may be kept s = ye>s4 ,! la/ fraction is kept 9 a sep>ate conta9]4 #dbj ,a l>ge excess ( acid is liable to int]f]e ) ! precipitation ( ! la/ traces ( cupric sulphide & is avoid$ 9 exact "w4 #dba ,noyes & ,bray use1 approximately1 ,h #j4be ,j4 ,am4 ,*em4 ,soc41 #bi1 #acg 7#aijg74 ,te/s 9 ?is laboratory %[$ t #a milligram ( cadmium-ion1 or ( lead-ion1 9 #ajj c4c41 is readily precipitat$ by hydrog5 sulphide 9 ! pres5ce ( #j4be mol> hydro*loric acid1 7,h #j4bb74 #dbb ,kahlbaum's ,kry/allviolett1 7,,*#c7b,,nc#f;,h#db;,c 3 ,c#f;,h#d,n7,,*#c7b;,cl1 is ref]r$ to4 #dbc ,an indelible ink p5cil 7violet7 may1 9 mo/ cases1 be us$ 9 place ( ! solution4 ,! details = ! application ( ! indicator are giv5 9 ! in/ructions = laboratory practice1 ,lab4 ,manual1 pp4 #ca1 #ajb1 #ajc4 #dbd ,see ,bly?1 ,poisons1 etc41 p4 #fjh 7#ahie71 9 reg>d to ! detection ( traces ( lead4 p#baf ,,*apt] ,,xii ,,! ,,copp] ,,& ,,silv] ,,gr\ps 7,cont9u$74--,,! ,,!ory ,,( ,,complex ,,ions ,we w n[ turn to ! consid]ation ( a s]ies ( reactions involv+ ! behavior ( s-call$ complex ions1 :i* are v frequ5tly met ) 9 ! v>i\s analytical gr\ps & :i* (f] valuable me?ods ( sep>ation & id5tification ( ions4 ,! behavior ( silv] nitrate solution t[>ds ammonia =ms a conv5i5t po9t ( attack 9 tak+ up ! g5]al subject4 ,action ( ,ammonia on ,silv] ,nitrate4--,addition ( ammonium hydroxide solution to silv] nitrate 7exp47 results 9 ! =mation ( a br[n precipitate ( silv] oxide 7& silv] hydroxide74 ,we may consid] ! sup]natant liquid to be saturat$ ) silv] hydroxide 7?is is 9 equilibrium ) silv] oxide71 & = ! saturat$ solution we may put ,ag ,,ho ,k,ag,o,h4 ,if m ammonium hydroxide is add$ to ! mixture1 ! precipitate dissolves readily4 ,! excess ( ammonium hydroxide mu/ increase ! conc5tration ( hydroxide-ion &1 if no o!r action occurr$1 we %\ld1 accord+ to ! pr9ciple ( ! solubility-product1 expect t ! precipitate w\ld !reby be slightly increas$ 7p4 #ade71 r ?an t x %\ld be dissolv$ s readily4 ,s9ce solution results ev5 :5 ! value ( ! "o factor1 ,,ho1 ( ! product is increas$1 we mu/ suspect t ! value ( ! o!r factor1 ! conc5tration ,ag ( silv]-ion1 is 9 "s way made mu* small] by ! addition ( ! excess ( ammonium hydroxide4 ,recall+ ! fact t alum9ium hydroxide is soluble 9 excess ( sodium hydroxide1 z ! result ( its amphot]ic "*1 a solution ( sodium alum9ate ,na,al,o#b be+ obta9$1 we might suspect t silv] hydroxide also has amphot]ic prop]ties1 i4e4 t x might be capable ( ioniz+ into arg5tate ions1 ,ag,o1 & hydrog5 ions1 ,ag,o,h ,ag,o ,h4 ,if su* be ! case1 ! nonioniz$ silv] hydroxide is 9 equilibrium1 n only ) ! solid phase1 p#bag b also ) two sets ( ions1 ,ag ,,ho ,ag,o,h ,ag,o,h ,ag,o ,h ,ag,o,h ,ag,o,h 1 & we mu/ h two solubility-product con/ants1 "o correspond+ to ! basic ionization 7see above7 & ! o!r correspond+ to ! acid ionization1 & ,ag,o ,h ,k,ag,o,h4 ,if silv] hydroxide h acid prop]ties1 ! addition ( an alkali mu/ suppress ! hydrog5-ion & ! hydroxide w g into solution z an arg5tate1 ,me,ag,o4 ,we f9d1 h[ev]1 t sodium or potassium hydroxide1 :i* w\ld =m an arg5tate v mu* m readily ?an ammonium hydroxide1 has no solv5t action on silv] hydroxide 7exp472 on ! contr>y1 quantitative exp]im5ts %[ t ! alkali makes ! hydroxide /ill less soluble ?an 9 pure wat]--z dem&$ by ! solubility-product = ! basic ionization4 ,x is ?us evid5t1 t ! solv5t action ( ammonium hydroxide is n due to its basic functions4 ,we w\ld suspect t we h "h an action1 9 :i* ammonia is ! active compon5t1 ! product ( a =m ( dissociation ( ammonium hydroxide1 ( :i* ! fix$ alkalies are incapable4 ,! ,complex ,silv]-,ammonium#dbe-;,ion4--,= a solution ( ammonia1 9 wat]1 we h ! rev]sible reactions3 p#bah ,,ho ,h ,,nh#c ,,nh#d ,,ho ,,nh#d,,oh1 & we note t a molecule ( ammonia appe>s to comb9e fir/ ) a hydrog5 ion1 to =m an ammonium ion1 & ?is !n =ms ammonium hydroxide ) ! hydroxide ion4 ,?is sugge/s t ammonia may h ! capacity to comb9e ) positive ions o!r ?an hydrog5 ion1 & ) metal hydroxides o!r ?an wat]4 ,= an analog\s reaction ( ammonia ) silv] ion & ) silv] hydroxide1 we w\ld h3 ,,nh#c ,ag ,,ho 7,,nh#c;,ag7 ,,ho 7,,nh#c;,ag7,,oh4 ,= ! condition ( equilibrium betwe5 ammonia1 ! silv]-ion & ! silv]-ammonium-ion1 we w\ld h#dbf3 ,,nh#c ,ag _/ ,,nh#c;,ag ,k4 ,exp]im5tal inve/igations ( ! quantitative relations1 obta9+ 9 ammoniacal solutions conta9+ silv] comp\nds1 %[ t no con/ant value is obta9$ = ! ratio1 z j develop$4 ,b ! exp]im5tal data %[ equally conclusively1#dbg t a con/ant is obta9$1 :5 ! conc5tration ( ! ammonia is rais$ to ! second p[]1 9 ! ma!matical /atem5t4 ,! significance ( ?is *ange 9 ! ma!matical relation1 x w be recall$ 7p4 #id71 is t two molecules ( ammonia mu/ comb9e ) "o silv] ion to =m an ion 7,,nh#c7b;,ag1 :]eas 9 ! =mation ( ! ammonium ion1 ,,nh#d1 we h a s+le molecule ( ammonia comb9+ ) "o hydrog5 ion4 ,we h !n #b ,,nh#c ,ag ,,ho 7,,nh#c7b;,ag ,,ho 7,,nh#c7b;,ag,,oh4 ,we w\ld ?us h a silv]-ammonium ion1 7,,nh#c7b;,ag1 & its hydroxide1 silv]-ammonium hydroxide1 correspond+ to ! p#bai ammonium ion & its hydroxide1 ammonium hydroxide4 ,! prop]ties ( ammoniacal solutions ( silv] oxide are 9 entire agreem5t ) ?is conception4 ,! hydroxide is a /rong] base ?an b>ium hydroxide4#dbh ,x =ms salts1 7,,nh#c7b;,ag,x1 9 :i* silv] appe>s z "p ( a s-call$ positive complex ion4 ,! hydroxide1 l ammonium hydroxide1 is un/able & is only kn[n 9 solution & 9 ! pres5ce ( free ammonia1 exactly z is ! case = ammonium hydroxide4 ,! ma!matical equation express+ ! equilibrium conditions = ! complex ion1 ,,nh#cb ,ag _/ 7,,nh#c7b;,ag ,k,in/ability1 gives a def9ite measure ( ! /ability ( ?is complex ion4 ,x is cle>1 t ! l>g] ! con/ant1 ! m un/able ! complex ion w\ld be1 & s ! con/ant is call$ ! ,in/ability ,con/ant#dbi ( ! complex silv]-ammonium-ion4 ,bodlnd] f\nd ! value ( ! con/ant to be #f4h;,e#h at #be4dcj ,accord+ to ! composition ( ! complex ion1 two molecules ( ammonia %\ld be requir$ = e molecule ( silv] nitrate1 to produce a solution conta9+ ! nitrate ( ! complex ion3 ,ag ,,no#c #b ,,nh#c 7,,nh#c7b;,ag ,,no#c4 ,z a matt] ( fact1 #bj c4c4 ( a mol> solution ( ammonium hydroxide 7 #bjj c4c4 ( a #j4a mol> solution7 mu/ be add$ to #ajj c4c4 ( a #j4a mol> solution ( silv] nitrate1 to conv]t ! silv] nitrate into ! salt ( ! complex silv]-ammonium-ion4 ,if ! ammonium hydroxide solution is all[$ to fl[ sl[ly1 f a pipette1 into ! silv] nitrate solution1 we f9d t ! la/ trace ( ! precipitat$ silv] hydroxide r$issolves j z ! la/ drop or two ( ! #bj c4c4 is add$ to ! mixture 7exp474 ,work+ m exactly1 ,rey*l]#dca f\nd t ! addition ( ammonia to a silv] nitrate solution1 9 ! proportion ( two molecules ( ! =m] to "o ( ! nitrate1 does n *ange ! freez+-po9t ( ! solution1 & !re=e p#bbj does n increase ! total numb] ( molecules 9 ! solution4 ,?is result agrees ) ! conception t two molecules ( ammonia comb9e ) "o silv] ion to =m a complex ion4 ,application 9 ,analysis4--,turn+ n[ to ! consid]ation ( ! be>+ ( ^! relations on ! detection ( silv]-ion 9 analysis1 we may conclude1 9 ! fir/ place1 f ! value ( ! con/ant z giv51 t only a small proportion ( ! total silv] 9 su* ammoniacal solutions is pres5t 9 ! =m ( silv]-ion2 b1 9 ! second place1 !re is1 at lea/1 a portion ( ! silv] pres5t 9 ! =m ( its ion--x is n entirely suppress$2 &1 9 ! ?ird place1 x is cle>1 f ! =m ( ! equilibrium equation1 t any excess ( ammonia mu/ v rapidly r$uce ! conc5tration ( silv]-ion 9 su* solutions4 ,! be>+ ( ^! relations1 :i*1 x w be not$1 conc]n conc5trations ( silv]-ion1 c be/ be se5 by work+ ) solutions ( def9ite conc5trations4 ,if ! solution we h j prep>$ is dilut$ ) wat] to #bjj c4c41 a #j4je mol> solution ( 7,,nh#c7b;,ag,,no#c is =m$4 ,9 su* a solution1 ! conc5tration1 ,ag1 ( ! silv]-ion is only #j4jjji1dcb :]eas 9 #j4je mol> silv] nitrate solution x is #j4jdce4 ,x is cle> t ! reactions ( ! silv]-ion w n be obs]v$ z readily 9 su* an ammoniacal solution z 9 a solution ( silv] nitrate1 :i* conta9s ! same conc5tration ( total silv]4 ,t su* is ! case1 may be readily demon/rat$ z foll[s3 ! addition ( #a c4c4 ( mol> sodium bromate to #aj c4c4 ( #j4je mol> silv] nitrate imm$iately =ms a heavy precipitate ( ! mod]ately difficultly soluble bromate1 ,ag,br,o#c1 :ile ! same addition to #aj c4c4 ( ! #j4je mol> silv]-ammonium nitrate solution produces no precipitate :atev] 7exp474 p#bba ,a lit] ( wat] dissolves #j4jbe mole 7#f grams7 ( silv] bromate#dcc at #ah4 ,if ! same degree ( ionization be assum$ = x z = a #j4jbe mol> solution ( ! analog\s salt1 silv] nitrate1 ,ag,n,o#c1 #ij ( ! silv] bromate 9 ! saturat$ solution is ioniz$4 ,! solubility-product con/ant !n is ,ag ,br,o#c 7#j4jbe #j4i7b #j4jjje4 ,:5 #a c4c4 ( mol> sodium bromate is add$ to #aj c4c4 ( #j4je mol> silv] nitrate1 ea* salt is ioniz$ #hj 9 ! mixture1 & ,ag #j4je #j4h #aj _/ #aa #j4jcg & ,br,o#c 7#a #a _/ #aa7 #j4h #j4jgb4 ,!n ! product ( ! ion conc5trations1 ,ag ,br,o#c #j4jcg #j4jgb #j4jjbg1 is consid]ably l>g] ?an ! con/ant #j4jjje & precipitation foll[s4 ,b1 :5 #a c4c4 ( mol> sodium bromate is add$ to #aj c4c4 ( a #j4je mol> silv]-ammonium nitrate solution1 ! conc5tration ( silv]-ion#dcd is #j4jjjhe & ! product ( ! ion conc5trations1 ,ag ,br,o#c #j4jjjhe #j4jgb #f;,e#e1 is small] ?an ! con/ant2 ! solution w n be saturat$ ) silv] bromate & no precipitate is =m$4 ,on ! o!r h&1 if #a c4c4 ( a #j4a mol> solution ( sodium *loride is add$ to #aj c4c4 ( #j4je mol> silv]-ammonium nitrate solution1 a v decid$ precipitate ( silv] *loride is =m$ 7exp474 ,! diff]5ce 9 ! action ( ! sodium bromate & ! *loride lies 9 ! fact t silv] *loride is #bejj times z insoluble z is silv] bromate1 & ! *loride may be precipitat$ f solutions conta9+ a v mu* small] conc5tration ( ! silv]-ion ?an is requir$ = ! precipitation ( silv] bromate4 ,! quantitative relations = ! *loride are z foll[s3 a lit] ( wat] dissolves #j4jjb gram1 or #a4d;,e#e mole1 ( silv] *loride at #be1dce & ! solubility-product con/ant at #be is ,ag ,cl 7#a4d;,e#e7b #b;,e#aj4 ,n[1 if #a c4c4 ( #j4a mol> sodium *loride is add$ to #aj c4c4 ( #j4je mol> silv]-ammonium nitrate1 we h1#dcf = ! fir/ mom5t1 ,ag #h4i;,e#d & p#bbb ,cl #j4jjh1 & ,ag ,cl #h4i;,e#d #j4jjh #g;,e#f1 :i* is mu* l>g] ?an ! solubility-product con/ant1 & precipitation mu/ take place4 ,! precipitate w be q a heavy "o3 z silv]-ion is remov$ f solution1 ! complex ion mu/ decompose & furni% a new supply ( silv]-ion1 & precipitation mu/ cont9ue until ! excess ( ammonia1 :i* is lib]at$ by ! decomposition ( ! complex ion 7,ag7,,nh#c7b ,cl ,ag,cl #b ,,nh#c71 suppresses ! silv]-ion suffici5tly to satisfy1 ) ! dim9i%$ conc5tration ( *loride-ion1 ! solubility-product con/ant ( silv] *loride4 ,x is cle> t1 :ile ! reactions ( silv]-ion are n obta9$ z readily 9 ! ammoniacal solution z 9 an equival5t solution ( silv] nitrate 7bromate exp]im5t71 nev]!less m s5sitive te/s %[ t a small portion ( ! silv] /ill is pres5t z silv]-ion 9 ! ammoniacal solution 7*loride exp]im5t74 ,?is br+s u to our ?ird po9t1 ! influ5ce ( an excess ( ammonia on ! conc5tration ( silv]-ion & on its reactions4 ,x is evid5t1 f ! =m ( ! equilibrium equation 7p4 #bai71 t any excess ( ammonia mu/ v rapidly r$uce ! conc5tration ( silv]-ion4 ,we may ask :at excess w be requir$ to prev5t ! precipitation ( silv] *loride 9 ! exp]im5t j tri$4 ,! "q may be answ]$ z foll[s3 ,! conc5tration ( *loride-ion1 :5 #a c4c4 ( #j4a mol> sodium *loride is add$ to #aj c4c4 ( #j4je mol> ,ag7,,nh#c7b,,no#c1 no precipitate be+ =m$1 w be #j4a 7#a _/ #aa7 #j4hg1 ! solution be+ dilut$ #a to #aa & ! p]c5tage ( ionization ( a salt ,me,x be+ approximately #hg 9 #j4je to #j4jf mol> conc5tration4 ,= a solution conta9+ ?is conc5tration ( *loride-ion1 ! conc5tration ,ag ( silv]-ion1 :i* may j be pres5t )\t lead+ to ! precipitation ( silv] *loride 7i4e4 = ! saturat$ solution7 is1 accord+ to ! pr9ciple ( ! solubility-product1 ,ag ,k,s4,p4 _/ ,cl 7#b;,e#aj7 _/ 7#j4a #j4hg #a _/ #aa74 ,fur!r1 9 ! pres5ce ( an excess ( ammonia1 practically all ( ! silv] is pres5t 9 ! complex =m1 &1 ,ag7,,nh#c7b #j4je #j4hg #aj _/ #aa ! #j4je mol> solution be+ dilut$ #aj p>ts to #aa & ! salt be+ #hg ioniz$4 ,if we call x ! conc5tration ( free ammonia requir$ to r$uce ! conc5tration ( silv]-ion to ! small value indicat$1 we may put ,,nh#cb ,ag _/ ,ag7,,nh#c7b x#b #b;,e#aj _/ 7#j4a #j4hg #a _/ #aa7 _/ 7#j4je #j4hg #aj _/ #aa7 #f4h;,e#h4 ,solv+ = x1 we obta9 x ,,nh#c #j4cc4 ,! conc5tration ( free ammonia1 necess>y to prev5t precipitation ( silv] *loride 9 ?is sy/em1 is !n p#bbc #j4cc1 in/ead ( #j4jjah1 pres5t 9 ! orig9al solution4 ,n[1 #aa c4c4 ( #j4cc mol> ammonia is equal to #aa #j4cc _/ #f1 or #j4fa c4c4 hexamol> ammonia4#dcg ,calculations1 bas$ on ! solubility-product con/ant ( silv] *loride & on ! in/ability con/ant ( silv]-ammonium-ion1 lead1 ?us1 to ! conclusion t an excess ( #j4fa c4c4 ( hexamol> ammonia is requir$1 9 #aj c4c4 ( #j4je mol> ,ag7,,nh#c7b,,no#c1 to prev5t ! precipitation ( silv] *loride by #a c4c4 ( #j4a mol> sodium *loride4 ,conv]sely1 ?is excess ( ammonia w be requir$ to r$issolve ! precipitate ( silv] *loride1 =m$ :5 #a c4c4 ( #j4a mol> sodium *loride solution is add$ to #aj c4c4 ( #j4je mol> ,ag7,,nh#c7b,,no#c4 ,! foll[+ exp]im5t %[s t su* is ! case4 ,,exp4 #a c4c4 ( #j4a mol> sodium *loride is add$ to #aj c4c4 ( #j4je mol> silv]-ammonium nitrate1 prep>$ z describ$ on p4 #bbj2 hexamol> ammonia is sl[ly add$ to ! mixture f a #a c4c4 pipette1 graduat$ 9 tw5tie?s ( a cubic c5timet]4 ,! precipitate w be se5 to be j ab\t completely dissolv$ :5 #j4f to #j4fe c4c4 ( ! ammonia solution has be5 us$4 ,we f9d1 9 ?is way1 t ! equilibrium equation = ! in/ability con/ant ( ! complex silv]-ammonium-ion1 toge!r ) ! pr9ciple ( ! solubility-product1 all[s a quantitative int]pretation ( ! problem ( ! behavior ( ammoniacal silv] solutions1 z f> z ! detection ( silv] by ! precipitation ( its salts is conc]n$4 ,if a /ill l>g] excess ( ammonia is us$ 7exp471 ev5 ! addition ( a #aj solution ( sodium *loride fails to precipitate ! *loride1 &1 vice v]sa1 ammonia 9 excess w readily r$issolve a heavy precipitate ( silv] *loride 7exp474 ,advantage is tak5 ( ?is fact 9 ! sep>ation & id5tification ( silv]-ion 7,laboratory ,manual1 q4 v474 ,x is int]e/+ to note t ! addition ( potassium bromide1 iodide or sulphide to ! ammoniacal solution1 9 :i* sodium *loride fails to precipitate any silv] *loride1 w /ill precipitate silv] bromide1 iodide or sulphide readily 7exp474 ,judg$ by ! l9e ( argum5t us$ above1 9 contra/+ ! behavior ( silv] bromate & silv] *loride1 ^! silv] salts p#bbd mu/ be /ill less soluble ?an ! *loride4 ,exp]im5t proves1 t su* is1 inde$1 ! case4#dch ,silv] iodide is s insoluble1 t ammonia#dci may be us$ to sep>ate x1 ) a consid]able degree ( accuracy1 f silv] *loride1 & ?is sep>ation =ms ! basis ( a me?od to detect *loride-ion 9 ! pres5ce ( an iodide4 ,if a solution ) a limit$ conc5tration ( ammonia is us$1 ! me?od may be ext5d$ also to ! sep>ation ( *lorides f bromides 7see ,*ap4 ,,xvi74#ddj ,complex ,metal-,ammonium ,ions ( ,copp]1 ,cadmium1 etc4--,q a numb] ( metal ions are capable ( =m+ m or less /able complex ions ) ammonia4 ,= analytical purposes1 ! mo/ int]e/+ ( su* complex ions1 aside f ! silv]-ammonium-ion1 are ^? =m$ by cupric1 cadmium1 z9c & nickel ions1 ! mo/ important ( :i* repres5t bival5t complex ions ( ! composition#dda ,me7,,nh#c7db4 ,! foll[+ in/ability con/ants h be5 det]m9$3#ddb ,at #ba1 ,cd#b ,,nh#cd _/ ,cd7,,nh#c7db #a;,e#g ,zn#b ,,nh#cd _/ ,zn7,,nh#c7db #b4f;,e#aj4 ,cupri-ammonium-ion is f> m int5sely blue ?an cupric-ion & its color is us$ z "o ( ! te/s to id5tify copp] 9 its salts4 ,nickel-ammonium-ion is also blue1 a mu* pal] blue1 & its color mu/ n be mi/ak5 z indicat+ ! pres5ce ( a dilute solution ( cupric-ammonium-ion4 ,! same k9d ( relations obta9 = ^! complex ions z = silv]-ammonium-ion4 ,= in/ance1 a salt l cupric phosphate1 :i* is readily precipitat$ f cupric sulphate solutions1 is n precipitat$ f ! ammoniacal solutions conta9+ an excess ( ammonia 7exp471 :ile ! v mu* less soluble#ddc cupric sulphide is readily precipitat$ ev5 f ! ammoniacal solutions 7exp474 ,x may p#bbe easily be %[n1 9 ! usual way1#ddd t ! sulphide ( copp] is v mu* less soluble ?an its phosphate 7exp474 ,! ,complex ,cyanide ,ions4--,metal ions are capable ( =m+ complex ions1 ( importance 9 analytical "w1 ) a numb] ( compon5ts o!r ?an ammonia4 ,among ! mo/ important ( ^! are ! complex ions =m$ ) cyanide-ion4 ,! !ory ( ! complex cyanide ions is entirely analog\s to t ( ! complex metal-ammonium ions1 b !re is a diff]5ce 9 /ability t makes _! special consid]ation desirable1 bo? = practical & = !oretical purposes4 ,! complex ions ( silv]-ion & cyanide-ion w be discuss$ fir/4 ,! ,arg5ticyanide-,ion4--,:5 potassium cyanide is add$ to a solution ( silv] nitrate1 a v insoluble precipitate ( silv] cyanide is obta9$1 b an excess ( potassium cyanide readily r$issolves ! precipitate 7exp474 ,s9ce solution is effect$ 9 spite ( ! pres5ce ( an excess ( ! precipitat+ cyanide-ion1 "o is l$ to suspect t ! o!r ion1 ! silv]-ion1 :i* is ne$$ to =m ! precipitate1 is suppress$ by ent]+ into "s k9d ( complex ) ! excess ( cyanide4 ,z a matt] ( fact1 ! solution conta9s a salt1 potassium arg5ticyanide ,k,ag7,,cn7#b1 9 :i* ! silv] =ms a "p ( a negative arg5ticyanide-ion 7,ag7,,cn7#b74dde ,if a curr5t ( electricity is pass$ ?r\gh su* a solution1 ! silv] 7all b traces71 toge!r ) ! cyanide gr\ps1 moves t[>ds ! positive electrode4#ddf ,! complex has be5 =m$1 !n1 by ! comb9ation ( a positive silv]-ion ) two negative cyanide ions1#ddg :i* produce a unival5t negative arg5ticyanide-ion1 ,ag7,,cn7#b4 ,recall+ ! fact t ! complex silv]-ammonium-ion is n p]fectly /able1 "o might suspect t ! complex cyanide-ion1 9 turn1 is n absolutely /able1 & t ! action1 by :i* x is =m$1 is balanc$1 :5 equilibrium is rea*$1 by a rev]se action ( decomposition4 ,we w\ld h1 !n1 p#bbf ,k ,ag #b 7,,cn7 ,k ,ag7,,cn7#b or1 m simply1 ,ag #b7;,,cn7 ,ag7,,cn7#b4 ,= ! condition ( equilibrium betwe5 ! complex & its compon5ts1 ! relation ,ag ,,cn#b _/ ,ag7,,cn7#b ,k,in/ability w\ld hold4 ,bodla5d]#ddh det]m9$ ! value ( ?is con/ant by measur+ ! conc5trations ( ! ?ree compon5ts "u v>y+ conditions4 ,! value f\nd is #a;,e#ba4 ,! value ( ! in/ability con/ant = ,ag7,,nh#c7b1 ( analog\s composition1 is #f4h;,e#h1 a v mu* l>g] value ?an ! con/ant ( ! ,ag7,,cn7#b complex4 ,! latt] is1 !re=e1 by f> ! m /able4 ,x mu/1 consequ5tly1 be mu* m difficult to obta9 reactions1 su* z precipitations1 ( silv]-ion 9 cyanide ?an 9 ammoniacal solutions4 ,9 fact1 x is impossible to precipitate silv] *loride by ! addition ( sodium *loride to ,k,ag7,,cn7#b solution 7exp474#ddi ,silv] sulphide 0 f\nd to be a mu* less p#bbg soluble salt ?an ! *loride 7p4 #bbd71 & ammonium or sodium sulphide solution1 :5 add$ to ! cyanide solution1 readily precipitates silv] sulphide 7exp474 7,! sulphide is capable ( exi/5ce 9 ! solid phase1 !re=e1 "u ^! conditions47 ,9 view ( ! extremely small conc5trations ( silv]-ion 9 ! cyanide solution1 we h "h a /rik+ illu/ration ( ! extreme insolubility ( ! sulphide4 ,accord+ to ! equilibrium equation giv5 above1 ! l>g] ! excess ( cyanide-ion 9 ! solution1 ! small] mu/ be ! conc5tration ( silv]-ion :i* is capable ( exi/5ce 9 its pres5ce4 ,9 agreem5t ) ?is conclusion1 we f9d t ! addition ( an excess ( potassium cyanide readily r$issolves ! precipitat$ silv] sulphide 7exp474#dej ,9 o!r words1 ev5 ! m9ute conc5tration ( silv]-ion1 t mu/ be pres5t 9 ! sup]natant liquid above a precipitate ( silv] sulphide 7,ag#b ,s#b ,k,sol4 ,prod41 = a saturat$ liquid71 _c be p]man5tly pres5t ) an excess ( potassium cyanide4 ,consequ5tly1 ! solid phase is incapable ( exi/5ce 9 ! sy/em4 ,! equilibrium equations give u1 ?us1 a compreh5sive basis = ! int]pretation ( ! behavior ( cyanide solutions conta9+ silv]4 ,fir/1 9 accordance ) ! small value ( ! con/ant1 we f9d x v mu* m difficult to obta9 precipitates ( silv] salts 9 cyanide1 ?an1 say1 9 ammoniacal solutions2 secondly1 9 accordance ) ! fact t a v small1 b def9ite1 conc5tration ( ! silv]-ion may /ill p]si/ 9 ! p#bbh sy/em1 we f9d x possible1 9 ! abs5ce ( an excess ( cyanide1 to precipitate su* an extremely insoluble silv] salt z silv] sulphide repres5ts2 & f9ally1 9 accordance ) ! =m & con/ant ( our equation1 we f9d x possible1 by us+ an excess ( potassium cyanide1 to suppress ! silv]-ion to ! po9t :]e ev5 ?is extremely insoluble salt c no long] exi/4#dea ,cuprocyanide & ,cadmicyanide ,ions4--,v _m ( ! metal ions are capable ( =m+ complexes ) cyanide-ion1 ( great] or small] degrees ( /ability1 &1 z is ! case = ! complex ions =m$ by metal ions ) ammonia1 a metal ion is frequ5tly able to =m m ?an "o complex ) cyanide-ion4#deb ,a numb] ( ^! complex cyanide ions are ( p>ticul> int]e/ 9 qualitative analysis4 ,= in/ance1 we make use ( ! diff]5ce 9 ! /ability ( ! cuprocyanide & ! cadmicyanide ions z (f]+ u ! mo/ conv5i5t me?od ( recogniz+ cadmium 9 ! pres5ce ( copp]4 ,except+ = ! sulphide & ! oxide1 cadmium does n =m salts & comp\nds ( *>act]i/ic colors1 &1 except 9 color1 ! salts resemble ! correspond+ copp] salts v mu* 9 _! physical & *emical behavior4 ,copp] & cadmium consequ5tly %[ ! same gr\p reactions 9 sy/ematic analysis4 ,! m int5se colors ( ! copp] comp\nds--! black sulphide1 ! int5sely blue cupric-ammonium-ion--mask ! cadmium reactions4 ,b cupric-ion may be conv]t$1 by potassium cyanide1 into a complex ion ( extreme /ability1 f ! solutions ( :i* hydrog5 sulphide & alkali sulphides fail to precipitate any sulphide ( copp]1 :ile cadmium sulphide may be precipitat$ f ! solutions ( ! mu* less /able complex cadmicyanide-ion4 ,:5 potassium cyanide is add$ to ! deep blue ammoniacal solution ( cupric-ammonium sulphate ,cu7,,nh#c7d,,s#d1 ! cupric-ion is r$uc$#dec p#bbi to cupr\s-ion1 & ! latt] is conv]t$1 by an excess ( cyanide1 into ! extremely /able complex ion ,cu7,,cn7#cb & its salt1 potassium cuprocyanide ,k#b;,cu7,,cn7#c4 ,! in/ability con/ant ( ! complex ion is3 ,cu ,,cn#c _/ ,cu7,,cn7#cb #j4e;,e#bg1 & ! conc5tration ( cupr\s-ion1 9 a #j4a mol> solution1 is approximately#ded #c4g;,e#h4 ,)\t an excess ( cyanide1 traces ( cupr\s sulphide may /ill be precipitat$1 b a few drops excess w prev5t ! precipitation entirely4#dee ,) an excess ( potassium cyanide1 cadmium =ms ! salt ,k#b;,cd7,,cn7#d1 yield+ ! ion ,cd7,,cn7#db4 ,! in/ability con/ant#def ( ! complex ion is ,cd#b ,,cn#d _/ ,cd7,,cn7#db #a4d;,e#ag4 ,! conc5tration ( cadmium-ion1 9 a #j4a mol> solution ( ! salt1 is !n approximately#deg #h;,e#e4 ,if potassium cyanide is add$ to an ammoniacal solution1 conta9+ bo? cadmium & copp]1 until ! color ( ! solution is j dis*>g$1 & if two or ?ree drops excess ( ! cyanide is !n us$1 ! addition ( ammonium sulphide w precipitate pure cadmium sulphide 7exp471 :ile ammonium sulphide1 add$ to a portion ( ! orig9al ammoniacal solution1 w precipitate a d>k mixture ( cupric & cadmium sulphide 7exp471 9 :i* ! yell[ color ( cadmium sulphide is mask$ by ! black precipitate ( cupric sulphide4 ,cobalticyanide & ,nickelocyanide ,ions4--,9 mu* ! same way1 9 ! id5tification ( nickel 9 ! pres5ce ( cobalt1 advantage may be tak5 ( ! fact t cobalt =ms an extremely /able cobalticyanide#deh ion1 ,co7,,cn7#fc1 :i* does n p]mit ( ! precipitation ( cobaltic hydroxide1 :]eas nickel does n =m su* an ion1 b only =ms a n v /able nickelocyanide ion1 ,ni7,,cn7#db1 :i* is readily decompos$ by brom9e & alkali1 nickelic hydroxide be+ precipitat$4 p#bcj ,! foll[+ are ! *ief actions involv$ 9 ! precipitation ( ! latt]3#dei ,ni7,,cn7#db ,ni#b #d ,,cn #b ,ni#b ,br#b #b ,ni#c #b ,br ,ni#c #c ,,ho ,ni7,,oh7#c ,applications & ,precautions 9 ,analysis4--,! complex cyanide ions ?us give u a conv5i5t means ( int]f]+ ) ! precipitation ( c]ta9 metal ions1 & ( enabl+ u1 !reby1 to detect o!r1 closely relat$1 ions 9 _! pres5ce4 ,at ! same "t1 we mu/ be c>eful to id5tify ! ions1 :i* we wi% to suppress1 be=e conv]t+ !m into ^! extremely /able complexes4 ,potassium cuprocyanide & potassium cobalticyanide solutions w\ld n give any ( ! ord9>y te/s = ions ( copp] & cobalt1 & to f9d ! latt] 9 su* solutions1 by ^! te/s1 we w\ld h to take ! tr\ble ( de/roy+ ! complexes4 ,%\ld ! de/ruction ( su* complexes become necess>y 7e4g4 :5 complex cyanide ions are pres5t 9 ! orig9al sub/ance "u exam9ation71 evaporation ) sulphuric acid1 ) due precautions aga9/ inhal+ poison\s hydrocyanic acid fumes1 fusion ) alkali c>bonates1 & p]haps mo/ conv5i5tly1 electrolysis ) suffici5tly high pot5tials1#dfj are ! me?ods mo/ frequ5tly employ$ = ! purpose4 ,x w be recall$ t we h us$ ! me?od ( fusion ) potassium c>bonate to f9d iron 9 potassium f]rocyanide 7p4 #hi74 ,f]rocyanide & ,f]ricyanide ,ions4--,! f]ro- & f]ricyanide ions may also be treat$ z complex ions4 ,= in/ance1 = ! f]ricyanide-ion1 we w\ld expect a condition ( equilibrium to exi/ betwe5 ! complex ion & ! simple ions accord+ to3 ,fe7,,cn7#fc ,fe#c #f ,,cn & ,fe#c ,,cn#f _/ ,fe7,,cn7#fc ,k4 p#bca ,if ! fact is recall$ t ! extremely s5sitive te/s = ! f]ric-ion fail to reveal ! lea/ trace ( x 9 a potassium f]ricyanide solution1 "o mu/ conclude t ! f]ricyanide-ion mu/ be extremely /able4 ,! conception ( ! f]ricyanide-ion z a complex ion1 subject to ! above equilibrium conditions1 sugge/s t if a consid]able excess ( hydrog5-ion is add$ to its solutions1 ! conc5tration ( f]ric-ion mu/ be increas$3 s9ce hydrocyanic acid is an extremely weak acid 7p4 #ajd71 ! ratio ,h ,,cn _/ ,,hcn hav+ ! value #g _/ #ajaj1 ! addition ( "s conc5trat$ hydro*loric acid mu/ decid$ly suppress ! cyanide-ion 9 a f]ricyanide solution & ?us lead to an increase 9 ! conc5tration ( ! f]ric-ion4 ,"u ^! conditions1 direct evid5ce ( ! pres5ce ( ! f]ric-ion1 & ( ! fact t ! complex ion is a compon5t 9 a rev]sible reaction1 may1 inde$1 be obta9$1 z well z fur!r evid5ce ( ! extreme /ability ( ! complex4 ,! pres5ce ( traces ( f]ric-ion may be detect$1 namely1 9 ! acid solution by ! ?iocyanate te/1 appli$ 9 its mo/ s5sitive =m1 9 :i* any f]ri?iocyanate produc$ is tak5 up 9 e!r4 ,,exp4 ,potassium f]ricyanide1 treat$ ) a ?iocyanate & e!r1 does n %[ ! lea/ trace ( color2 :5 "s conc5trat$ hydro*loric acid is add$ to ! mixture1 a p]fectly pla91 al?\gh noticeably fa9t1 p9k t9t is imp>t$ to ! e!r solution4 ,m]curic cyanide1 z we h se5 7p4 #aae71 is exceptional 9 its exce$+ly small capacity = ionization4 ,%]rill#dfa has f\nd t ! dissociation con/ant = ,hg#b ,,cn#d _/ ,hg7,,cn7#db has ! extremely small value #j4d;,e#da4 ,consequ5tly1 m]curic-ion mu/ be ev5 m effective ?an hydrog5-ion 7/rong acids71 9 suppress+ ! cyanide-ion & lib]at+ ! f]r\s- or f]ric-ion1 9 solutions ( f]rocyanides or f]ricyanides4 ,9 fact1 :5 a solution ( potassium f]rocyanide is w>m$1 = a mom5t1 ) "s m]curic oxide1 ! f]rocyanide complex is to "s ext5t decompos$2 ! lib]at$ f]r\s-ion is oxidiz$1 by ! excess ( m]curic oxide1#dfb to f]ric-ion1 & ! pres5ce ( ! latt]1 9 quantity1 is %[n by ! abundant precipitation ( f]ric f]rocyanide or ,prussian blue1 :5 ! mixture is acidifi$ ) hydro*loric acid 7exp474 p#bcb ,! ,aurocyanide-,ion4--,gold =ms a p>ticul>ly /able complex ion ) cyanide-ion4 ,! con/ant#dfc = ! ratio ,au ,,cn#b _/ ,au7,,cn7#b has ! value #ajbh4 ,?is makes potassium cyanide an excell5t solv5t = insoluble gold comp\nds1 su* z gold sulphide1 & ! cyanide process = ! extraction ( gold ores makes use ( ?is prop]ty4 ,! ,react+ ,compon5ts 9 ,solutions ( ! ,complex ,cyanide ,ions4--,! extraord9>y values1 obta9$ = ! con/ants express+ ! condition ( equilibrium betwe5 cyanide ions & "s ( ! simple metal ions1 su* z gold & silv] ions1 & _! complex ions1 h l$ to inquiries conc]n+ a "q ( fundam5tal int]e/ 9 ! !ory ( complex ions & 9 ! !ory ( ionization itself4 ,9 a #j4je mol> solution ( ,k,ag7,,cn7#b1 conta9+ an excess ( #j4a mole ( ,,cn1 p] lit]1 ! conc5tration ( silv]-ion is only #e;,e#ba4 ,& yet1 ! addition ( potassium hydrosulphide 7suffici5t to make ,,k% #j4a mol>7 w precipitate silv] sulphide practically in/antane\sly f ! solution4#dfd ,9 solutions conta9+ a l>g] excess ( cyanide1 ! conc5tration ( ! silv]-ion is enorm\sly r$uc$1 & yet1 :ile we c no long] precipitate silv] sulphide f su* a solution1 metallic silv] may be precipitat$ by z9c or by ! action ( an electric pot5tial at ! ca?ode 7,*apt] ,,xv74 ,! "q may be ask$1 :e!r we mu/ consid] t 9 ^! actions ! m9ute quantity ( free silv] ions1 pres5t at any mom5t1 is alone capable ( ! reactions indicat$1 & t ! decomposition ( ! complex into its compon5ts--z "o ( ^!1 ! silv]-ion1 is remov$ by precipitation--takes place ) suffici5t spe$ to acc\nt = ! rapid actions1 :olly1 z direct actions ( ! silv] ions4 ,! alt]native to an affirmative answ] to ?is "q is1 t silv] sulphide or silv] may be precipitat$ by direct action ( ! precipitant on ! complex ions1 r ?an on ! silv] ions4 ,we may indicate ! fir/ c\rse sugge/$ = ! action1 z foll[s3 #b ,ag7,,cn7#b ,s#b #d ,,cn #b ,ag ,s#b ,ag#b,s #d ,,cn4 ,i ,! second1 sugge/$1 c\rse ( ! action w\ld be ! foll[+3 #b ,ag7,,cn7#b ,s#b ,ag#b,s #d ,,cn4 ,,ii ,?is second action w\ld mean t we c\ld obta9 reactions ( silv] ions1 su* z ! precipitation ( silv] sulphide1 )\t ! int]m$iate =mation ( ! free ions !mselves4 ,! consequ5ces ( ! fir/1 ! ord9>y1 conception ( su* actions z direct actions ( silv] ions1 h be5 analyz$ by ,hab]#dfe f ! po9t ( view ( ! velocities ( ! actions1 by :i* ! complex mu/ be =m$ f its compon5ts & be decompos$ into !m1 9 ord] to satisfy ! facts conc]n+ ! precipitations4 p#bcc ,we may consid]1 ) ,hab]1 a lit] ( a #j4je mol> solution ( ,k#b;,ag7,,cn7#c1 conta9+ an excess#dff ( #j4ie mole potassium cyanide4 ,9 su* a solution1 ! conc5tration ( silv]-ion is r$uc$ to #h;,e#bd gram-ion p] lit]4 ,n[1 accord+ to ! be/ det]m9ations ( ! ultimate dim5sions ( molecules1 ab\t #ajbd molecules are e/imat$ to be conta9$ 9 a mole 7gram-molecule71 & #ajbd ions1 !re=e1 9 a gram-ion 7e4g4 9 #ajh grams ( silv]-ion !re w\ld be #ajbd individual silv] ions74 ,!n a lit] ( ! solution we are consid]+ w\ld conta91 at any mom5t1 only eight individual silv] ions1 :i* are diff]5t ones f mom5t to mom5t1 s9ce ! rev]sible reactions ,ag #c ,,cn ,ag7,,cn7#cb1 are go+ on cont9ually4 ,?us #ajj c4c4 ( ! solution w\ld n conta9 ev5 "o silv] ion all ! "t1 b ! requirem5ts ( ! equilibrium conditions c\ld be met#dfg by silv] ions fla%+ up & disappe>+ 9 su* a way1 t ! requir$ av]age conc5tration 9 unit "t is ma9ta9$4 ,!re is no?+ irrational 9 su* a conception4 ,"o may ask1 h[ev]1 :at mu/ be ! velocities1 ) :i* ! complex is =m$ f ! compon5ts1 & is resolv$ into !m1 9 ord] to satisfy an in/ability con/ant#dff #ajbb & /ill enable u to obta9 a practically in/antane\s precipitation1 say ( silv] sulphide1 ! action be+ analyz$ on ! basis ( ! ord9>y conception t only ! silv]-ion itself1 & n ! complex ion1 is directly active 9 ! =mation ( ! silv] sulphide4 ,a condition ( equilibrium1 9 a rev]sible action1 implies t ! velocities ( ! two cont9u\s1 oppos$ reactions are equal 7p4 #id74 ,= ! action ,ag #c ,,cn ,ag7,,cn7#cb ! velocity ( =mation ( ! complex is proportional to a *>act]i/ic con/ant1 ,k,=mation1 to ! conc5tration1 ,ag1 ( ! silv]-ion1 & to ! ?ird p[] 7see p4 #id7 ( ! conc5tration1 ,,cn1 ( ! cyanide-ion4 ,! velocity ( ! oppos$ reaction ( decomposition ( ! complex is proportional to ano!r *>act]i/ic con/ant1 ,k,decomposition1 & to ! conc5tration1 ,ag7,,cn7#cb1 ( ! complex ion4 ,= ! condition ( equilibrium1 ! velocities ( ! oppos$ reactions are equal1 & we d]ive ! relation3 ,ag ,,cn#c _/ ,ag7,,cn7#cb ,k,decomposition _/ ,k,=mation #a _/ #ajbb4 ,! equilibrium con/ant ( ! complex ion is1 !n1 ! ratio ( ! velocity con/ants ( its decomposition & =mation 7see p4 #id74 ,n[1 ! velocity con/ant1 ,k,=mation1 repres5ts ! conc5tration1 9 moles1 ( ! complex ion ,ag7,,cn7#cb1t is =m$ 9 unit "t f unit conc5trations ( its compon5ts ,ag & ,,cn1 & x may be consid]$ z ! reciprocal ( a "t con/ant1 ,t,=mation1 ! "t requir$ to =m unit conc5tration ( ! complex ion1 :ile ! compon5ts are ma9ta9$ at unit conc5tration4 ,! analog\s reciprocal relation holds = ! velocity con/ant1 ,k,decomposition1 & a "t con/ant1 ,t,decomposition4 ,! equilibrium equation1 !re=e1 expresses also ! foll[+ relations3#dfh p#bcd ,ag ,,cn#c _/ ,ag7,,cn7#cb ,t,=mation _/ ,t,decomposition #a _/ #ajbb4 ,9 words1 ! "t requir$ = ! spontane\s decomposition ( "o mole ( ! complex is #ajbb times z long z ! "t requir$ to =m "o mole ( ! complex1 f uni=mly unit conc5trations ( ! compon5ts4 ,if ! conc5tration ( silv]-ion is r$uc$ to #a _/ #ajbb & ! conc5trations ( ! cyanide-ion & ! complex ion are ma9ta9$ at #a1 ! =mation ( ! complex takes place #ajbb times z sl[ly z :5 ,ag #a1 & a condition ( equilibrium is produc$1 ! "t requir$ to decompose & to =m ! same am\nt ( ! complex be+ n[ equal4 ,?is relation ( "t con/ants may be us$ to obta9 "s idea ( ! consequ5ces ( assum+ c]ta9 limit+ values = "o or ! o!r1 ! ratio be+ ma9ta9$ at ! value #a _/ #ajbb4 ,if ! "t con/ant ,t,=mation = ! =mation ( ! complex be tak5 z "o t5-?\s&? ( a second1#dfi !n1 accord+ to ,hab]1 a mol> solution ( potassium arg5ticyanide w\ld n be able to =m 9 ?\s&s ( ye>s suffici5t silv] ions to be discov]$ by any direct te/1 a result :i* is n compatible ) ! precipitation ( silv] sulphide & ( metallic silv] 9 a few m9utes1 s9ce silv] ions c\ld n be suppli$ rapidly en\gh4 ,x is evid5t1 ?us1 t ! ratio #a _/ #ajbb mu/ indicate an exce$+ly small value = ,t,=mation1 if only silv] ions =m silv] sulphide & silv]4 ,if we assume t ! complex is decompos$ s fa/ z to supply new silv] ions rapidly en\gh1 to all[ u to consid] ! precipitation ( silv] & silv] sulphide z direct actions ( ! silv] ions1 !n we may1 cons]vatively1 consid] ,t,decomposition to be ab\t #a _/ #ajj second4 ,!n ,t,=mation w\ld be only #a _/ #ajbd second4 ,consid]+ ! limit+ results = ! dim5sions ( atoms 7& ions7 & tak+ acc\nt ( ! fact t ! =mation ( ! complex involves electrical *anges1 t is1 9 mod]n t]ms1 *anges 9 position ( electrons1#dgj ,hab] f9ds1 t to satisfy ! above value = ! "t con/ant1 su* *anges mu/ involve a motion ( electrical *>ges at a spe$ ab\t a million times z great z ! velocity ( light4 ,su* a velocity is1 unque/ionably1 incompatible ) our k ( ! velocities ( light & ( electrical *>ges4 ,we mu/ draw ! conclusion t ! complex arg5ticyanide-ion probably _c decompose fa/ en\gh into its ions1 to enable ! latt] to be ! only compon5ts :i* make x possible to precipitate silv] sulphide or metallic silv] f its solutions#dga 7see above1 p4 #bcb74 ,t w\ld make x necess>y to assume direct action p#bce 7z giv5 9 equation ,,ii1 p4 #bcb7 betwe5 ! complex & ! precipitat+ ag5t1 to "s ext5t1 at lea/1 ! ext5t be+ dep5d5t on ! conc5trations involv$ 9 a giv5 case4 ,if fur!r inve/igations %\ld confirm su* a view1 we w\ld probably f9d t bo? ! actions "u consid]ation 7equations ,i & ,,ii1 p4 #bcb7 mu/ proce$ simultane\sly4 ,! second "o w\ld h ! advantage ( enorm\sly great] conc5trations ( ! react+ compon5ts1 e4g4 ( ! complex ion2 ! fir/ "o w\ld1 probably1 be f\nd to h ! advantage ( an enorm\sly great] velocity con/ant4 ,! actual velocities ( ! two reactions h nev] be5 measur$#dgb & no f9al explanation ( ! relations c be (f]$4 ,! problem is a v important "o1 involv+ ! :ole "q ( ! mode ( ionic action 7cf4 ,*ap4 ,v1 especially p4 #hc74 ,aside f ! !oretical value ( ! problem t has be5 rais$1 ! "q ( imm$iate mom5t to u1 f ! po9t ( view ( analytical *emi/ry1 is ! "q :e!r su* conclusions w\ld invalidate1 9 any way1 ! use we h made ( ! !ory ( complex ions1 9 elucidat+ ! "q ( ! precipitation & nonprecipitation ( salts ( simple ions f solutions ( _! complex ions4 ,! exi/5ce ( a precipitate 9 contact ) a solution is a "q ( a condition ( equilibrium2 ! "q rais$1 z ! result ( ,hab]'s calculations1 deals simply ) ! problem ( ! pa?1 ! me*anism by :i* equilibrium is rea*$1 b ! answ] to x does n affect ! conditions1 on :i* ! ma9t5ance ( equilibrium dep5ds4 ,all ! conclusions1 drawn 9 our discussions ( precipitation f solutions ( complex ions1 are conc]n$ ) f9al conditions = equilibrium1 i4e4 ) ! conditions "u :i* a precipitate c exi/1 & n ) ! me*anism ( its =mation4 ,! conclusions rea*$ are valid1 !re=e1 irrespective ( :at ! decision may ultimately be 9 ! "q1 :e!r ! simple ions alone are act$ ^u1 :5 _! salts are precipitat$1 or :e!r ! complex ions are also imm$iately conc]n$ 9 ! action4 ,! precipitation ( silv] *loride f an ammoniacal solution#dgc may s]ve to illu/rate ?is po9t4 ,9 ! fir/ place1 ! precipitation ( silv] *loride f an ammoniacal solution1 say by sodium *loride1 may be consid]$ to be ! result ( ! direct int]action ( *loride ions ) ! small quantity ( silv] ions pres5t1 ! complex s]v+ only to r5ew ! supply ( silv] ions1 z ! latt] are remov$ f solution1 by ! precipitation4 ,! c\rse ( ! action w\ld be express$ by ! equations ,ag7,,nh#c7b;,cl ,ag7,,nh#c7b ,cl #b ,,nh#c ,ag ,cl ,ag,cl #b ,,nh#c4 7#a7 ,ag,cl ,ag,cl ,:5 ! precipitation is end$ & equilibrium e/abli%$1 a trace ( silv] *loride is 9 solution1 9 contact ) ! precipitate1 &1 accord+ p#bcf to ! pr9ciple ( ! solubility-product1 we mu/ h ,ag ,cl ,k,ag,cl4 ,bodlnd]'s exp]im5ts1#dgd on ! solubility ( silv] *loride 9 ammonia1 prove t ?is relation is 9 p]fect agreem5t ) ! facts4 ,= ! silv]-ammonium-ion1 ! free ammonia & ! silv]-ion pres5t 9 ! solution1 we mu/ h ! relation ,ag ,,nh#cb _/ ,ag7,,nh#c7b ,k,in/ab4 ,con/44 ,?is relation1 accord+ to ! exp]im5tal evid5ce1 is also f\nd to hold4 ,n[1 we might1 on ! o!r h&1 assume t ! prim>y or ma9 action1 lead+ to ! precipitation ( silv] *loride1 is ! int]action ( ! *loride ions ) ! complex ions1 r ?an ) silv] ions4 ,silv]-ammonium *loride1 ,ag7,,nh#c7b;,cl1 might fir/ be =m$1 = in/ance1 & !n decompose directly into silv] *loride & ammonia4 ,?is is ! simple/ assumption we c make = ?is k9d ( action & is suffici5tly illu/rative ( any k9d ( direct action betwe5 ! *loride ions & ! complex ions4 ,! pa? ( ! action w\ld !n be express$ by ! equations ,ag7,,nh#c7b ,cl ,ag7,,nh#c7b;,cl #b ,,nh#c ,ag,cl #b ,,nh#c ,ag ,cl4 7#b7 ,ag,cl ,ag,cl ,x is cle>1 f a comp>ison ( ?is s]ies ( equations ) equations 7#a71 t !y repres5t ! same rev]sible reactions 9 a some:at diff]5t ord]4 ,s9ce equilibrium conditions = any rev]sible reaction 7e4g4 = ,a ,b ,c ,d7 are indep5d5t ( ! ord] 9 :i* ! compon5ts 7e4g4 ,a1 ,b1 ,c1 ,d7 are br\ght into ! sy/em 7p4 #id71 ! diff]5ce ( ord]1 indicat$ by equations 7#a7 & 7#b71 _c affect ! f9al condition ( equilibrium 9 ! sy/em "u discussion4 ,= in/ance1 s9ce we aga9 h silv] *loride 9 contact ) its saturat$ solution1 we aga9 mu/ h ,ag ,cl ,k,ag,cl1 & ! exp]im5tal confirmation ( ?is relation 7& simil>ly ( ! relation ,ag ,,nh#cb _/ ,ag7,,nh#c7b ,k7 agrees z well ) ?is second pa? ( ! action z ) ! fir/4 ,conv]sely1 s9ce ! pa?1 by :i* ! equilibrium is rea*$1 does n affect ! condition ( equilibrium1 x is p]fectly legitimate to draw conclusions f equilibrium con/ants1 )\t assum+ to "k any?+ at all ab\t ! pa? by :i* ! condition is rea*$4#dge ,= analytical "w1 ! vital po9t is ! ultimate condition ( equilibrium1 :i* det]m9es :e!r a precipitate may exi/ & be =m$ 9 a giv5 sy/em or n4 ,! in/ability con/ants ( ! complex ions & ! solubility-product con/ants ( precipitates are ! con/ant factors involv$ 9 ! ultimate conditions = equilibrium1 & !y d n dep5d on ! pa? by :i* equilibrium is rea*$4 ,consequ5tly1 we f9d t ! application ( p#bcg ! !ory ( complex ions to analytical problems ( precipitation has be5 9 no wise invalidat$ by ! problems pres5t$ by ,hab]4 ,! !ory =ms n[1 z be=e1 9 fact1 ! be/ quantitative basis = ! expression ( ! exp]im5tal results4 ,! /ability con/ants1 & ! conc5trations ( ! compon5ts us$1 det]m9e ! limit+ conc5trations 9 :i* a giv5 metal ion is capable ( cont9u$ exi/5ce1 & det]m9e1 !re=e1 ! "q :e!r an ionog51 ( a giv5 solubility1 is capable ( exi/5ce z a solid phase 9 a giv5 sy/em4 ,! ,/ructure ( ,complex ,ions4--,! ability ( ammonia to =m complex ions ) simple metal ions is commonly ascrib$ to ! unsaturat$ condition ( ammonia 7see p4 #fe74 ,x is int]e/+ to recall ! fact1 t ! m>k$ p[] ( ! cyanide-ion to =m complexes ( extraord9>y /ability1 is also associat$ ) a simil>ly unsaturat$ condition ( ! cyanide-ion 7p4 #ff74 ,accord+ to ! results ( ,nef's rese>*es1#dgf we h1 9 hydrocyanic acid & ! cyanides1 unsaturat$ or bival5t c>bon2 potassium cyanide1 = in/ance1 has ! /ructure ,k--,n,c4 ,! two free val5ces ( ! c>bon atom may1 accord+ to ! electrical !ory ( val5ce1 be aga9 consid]$ to consi/ ( "o negative & "o positive *>ge4 ,! possibility ( ! =mation ( complexes is !n self-evid5t1 & we c readily see1 h[ silv] cyanide1 ,ag--,n,c1 %\ld absorb cyanide-ion1#dgg ,c,n1 & =m a complex 7,ag--,n,c,c,n7 or ,ag7,,cn7#b1 ^: potassium salt w\ld be potassium arg5ticyanide1 ,k,ag7,,cn7#b4 ,= ! potassium salt ,k#b;,ag7,,cn7#c1 ( ! second complex ion#dgh ,ag7,,cn7#cb ( silv] & cyanog51 ! mo/ likely /ructure is ,ag--,n,c--,c,n--,k4 _/ ,c,n--,k ,! o!r complex cyanide ions1 f]rocyanide1 f]ricyanide1 cobalticyanide1 etc41 are consid]$ to h /ructures entirely simil> to ^? giv5 to ! arg5ticyanide ions4#dgi ,complex ,halide1 ,sulphide1 ,oxide & ,oxonium ,ions4--,9 conclusion1 !re are o!r elem5ts besides nitrog5 79 ammonia & its d]ivatives7 & c>bon 79 cyanides71 :i* =m complex ions ) simple ions2 notably ! halog5s =m su* complexes4 ,*loroplat9ic acid1 ,h#b,pt,cl#f1 & its salts 7,lab4 ,manual1 q4 v471 fluorosilicic acid1 ,h#b,si,f#f1 potassium-m]curic iodide1 p#bch ,k,hg,i#c & ,k#b ,hg,i#d1dhj :i* =ms a mo/ s5sitive reag5t = ! detection ( traces ( ammonia1#dha are in/ances ( complexes ( ! halog5s t are ( importance 9 analysis4 ,x is wor?y ( note t ! mo/ likely /ructure#dhb = ^! comp\nds1 e4g4 ,cl#b,pt7,cl,cl--,h7#b1 be>s a v /rik+ analogy to ! /ructures frequ5tly assign$ to ! cyanide & ammonia complex ions4 ,oxyg5 & sulphur =m complex ions1 ( great /ability1 ) _m elem5ts1 & we %all pres5tly h occasion to discuss 9 detail "s ( ! complex ions =m$ by sulphur4 ,all ( ! oxyg5 acids may be treat$ z conta9+ complex ions ( oxyg5 & "s o!r elem5t1 & _! in/ability con/ants#dhc are factors 9 det]m9+ _! *emical behavior4 ,= in/ance1 su* is ! case1 mo/ likely1 = _! behavior z oxidiz+ & r$uc+ ag5ts 7see ,*apt] ,,xvi74 ,! unsaturat$ condition ( oxyg5 9 wat]1 7,h#b,o71 makes possible1 also1 ! =mation ( complex ions1 7,h#b,o7x,me1 etc41 call$ oxonium ions & comp>able ) metal-ammonium ions4 ,!y =m a mo/ invit+ field = rigor\s inve/igation4 ,x is altoge!r probable t ! hydrog5-ion is intimately relat$1 9 aque\s acid solutions1 to ! complex oxonium-ion1 7,h#b,o7x,h1 comp>able ) ! ammonium-ion1 7,,nh#c;,h71 &1 possibly1 ! great] "p ( ! hydrog5-ion1 9 aque\s solutions1 exi/s 9 ?is =m ( comb9ation4#dhd ,complex ,ions ( ,organic ,oxyg5 ,d]ivatives4--,a fur!r gr\p ( complex ions1 d]iv$ f organic d]ivatives ( oxyg51 are ( p>ticul> importance 9 analytical "w4 ,_m organic comp\nds1 su* z sug>s1 glyc]9e1 t>trates1 citrates1 int]f]e1 m or less1 ) ! precipitation ( metal hydroxides & c]ta9 ( _! salts4 ,= in/ance1 ! addition ( cane sug> or ( ro*elle salt 7sodium potassium t>trate7 to a solution ( p#bci cupric sulphate prev5ts ! subsequ5t precipitation ( cupric hydroxide by alkali 7exp474 ,9 place ( a precipitate ( ! hydroxide1 a cle>1 int5sely blue1 solution is =m$4 ,9 an analog\s way1 ! same sub/ances & simil> comp\nds int]f]e ) ! precipitation ( ! hydroxides ( alum9ium & *romium1 & s9ce alum9ium & *romium %\ld be precipitat$ z hydroxides 9 sy/ematic analysis 7,*ap4 ,x71 ! pres5ce ( su* organic comp\nds mu/ be mo/ c>efully consid]$1 to avoid error4#dhe ,! precipitation ( mod]ately difficultly soluble salts1 su* z phosphates1 is also r5d]$1 appreciably1 m difficult4 ,only extremely insoluble salts1 su* z ! sulphides ( ! ars5ic1 copp] & z9c gr\ps1 are precipitat$1 f solutions ( organic sub/ances ( ! "* indicat$1 )\t any appreciable int]f]5ce4#dhf ,^! relations cle>ly recall ! *>act]i/ic behavior ( ammoniacal & cyanide solutions1 9 :i* complex ions are =m$1 & ! int]f]5ce ( ! organic comp\nds ) precipitation is ( a simil> nature--complex ions are =m$ by metal ions ) ^! organic comp\nds1 & ! complexes are1 9 _m in/ances1 suffici5tly /able to r$uce ! conc5trations ( ! metal ions to ! po9t1 :]e only v difficultly soluble salts c be precipitat$4 ,! relations may be illu/rat$ by ! discussion ( ! complex =m$ by ! cupric-ion ) t>trates4 ,! /ructure ( sodium t>trate is express$ by ,na,o#b;,c--,,*7,,oh7--,,*7,,oh7--,,co#b ,na4 ,! und]scor$ hydroxide gr\ps ,,oh are kn[n 9 organic *emi/ry z alcohol gr\ps4#dhg ,n[1 alcohols resemble wat] 9 v _m prop]ties &1 among o!rs1 9 ! capacity to =m metal d]ivatives or alcoholates1 9 :i* ! hydrog5 7ion7 ( ! hydroxide gr\p is replac$ by metal ions4 ,! alcoholates correspond1 ?us1 to ! metal hydroxides1 :i* are ! analog\s p#bdj d]ivatives ( wat]4 ,exactly z !re is a va/ diff]5ce 9 ! read9ess ) :i* ! v>i\s metal hydroxides1 or bases1 ionize1 _m ( !m be+ only slightly ionizable 7! weake/ bases71 s c]ta9 alcoholates are mu* less readily ionizable ?an o!rs4 ,! alkali alcoholates are mo/ readily ioniz$4 ,:5 sodium t>trate is mix$ ) an excess ( sodium hydroxide1 "s ( ! readily ionizable sodium salt ( ! alcohol gr\ps ( ! sodium t>trate is =m$ & we h3 7,c,h,o,na7#b7;,,co#b7b #b ,na 7,,*o7#b7;,,co#b7b #d ,na4 ,:5 cupric sulphate is add$ to ?is mixture1 a slightly ionizable complex cupri-t>trate-ion is =m$ by ! union ( ! cupric-ion ) ! alcoholate-t>trate-ion3 7,,*o7#b7;,,co#b7b ,cu#b 7,,*o7#b;,cu7,,co#b7b4 ,! complex ion is n p]fectly /able & s ! action is a rev]sible "o1 z indicat$ 9 ! equation4 ,! great] portion ( ! copp]1 h[ev]1 is pres5t z "p ( ! complex negative ion ( cupric-t>t>ic acid & its salts4 ,?is may be demon/rat$ by subject+ ! solution to electrolysis 9 a ,u-tube 7p4 #de74 ,x is readily se5 7exp47 t a deep blue ion1 obvi\sly conta9+ copp]1 migrates to ! positive pole4#dhh ,! conc5tration ( cupric-ion is s small t its hydroxide & its phosphate are n precipitat$ f ! solution by ! addition1 respectively1 ( alkali or ( a soluble phosphate 7exp474 ,cupric sulphide1 h[ev]1 is s insoluble t x may be precipitat$ completely f ! solution by ! addition ( a sulphide 7exp471 ! conc5tration ( cupric-ion be+ mu* small] 9 ! saturat$ solution ( ! sulphide ?an 9 ! solution ( sodium cupri-t>trate4 ,citrates1 sug>s1 glyc]9e1 conta9 alcoholic gr\ps ( ! same nature z f\nd 9 ! t>trates1 & !y are capable ( =m+ simil> complexes1 or little ionizable alcoholates1 ) metal ions4 ,c]ta9 organic acids1 :i* conta9 no alcohol gr\ps1#dhi are p#bda also capable ( =m+ fairly /able complexes ) metal ions3 ?us1 acetates =m a complex ) lead-ion1 t is suffici5tly /able to r5d] lead sulphate1 :i* is difficultly soluble 9 wat]1 readily soluble 9 ammonium acetate solution#dij 7exp474 ,soluble oxalates readily comb9e ) f]ric1 f]r\s1 cupric & o!r oxalates & int]f]e1 m or less1 ) ! detection ( ! metal ions1 z ! result ( complex =mations4 ,all ( ^! complexes are decompos$ r readily by ! addition ( /rong acids1 ^: hydrog5-ion breaks up ! complex ions1 by suppress+ ! anions#dia ( ! mu* weak] organic acids & alcohols4 ,consequ5tly1 ^! organic comp\nds d n int]f]e ) te/s :i* may be c>ri$ out 9 /rongly acid solution4 ,= in/ance1 ! addition ( potassium f]rocyanide to a solution ( ammonium f]rioxalate 7,,nh#d7c;,fe7,c#b,o#d7c1 to :i* an excess ( ammonium oxalate has be5 add$1 gives only a slight indication ( ! pres5ce ( f]ric-ion 7a gre5i% blue solution is obta9$72 :5 hydro*loric acid1 9 excess1 is add$ to ! mixture1 ,prussian blue1 f]ric f]rocyanide1 is imm$iately precipitat$ 9 quantity 7exp474 ,,footnotes3 #dbe ,! nam+ ( ! complex ions1 :i* ammonia =ms ) metal ions1 has n yet be5 satisfactorily settl$4 ,engli% writ]s frequ5tly speak ( ammonio-arg5tic ion & ammonio-arg5tic nitrate4 ,g]man writ]s speak ( ,silb]-ammoniak ion 7,abegg1 ,h&b4 d] anorg4 ,*em41 ,,ii1 #gbh71 :i* w\ld read silv]-ammonia ion 9 ,engli% t]ms4 ,! t]m9ology silv]-ammonium ion1 us$ 9 ?is book1 is bas$ on ! idea1 t all ^! complex ions are ess5tially ( ! same nature z ! well-kn[n ammonium-ion1 ,,nh#d1 ! positive *>ge be+1 almo/ c]ta9ly1 c>ri$ by nitrog5 9 ^! complex ions1 z x is 9 ammonium-ion4 ,! latt] is a complex ion ( ammonia ) hydrog5-ion4 ,! "n ammonio-arg5tic ion does n br+ out ?is close relation%ip & puts ! emphasis on ! silv]1 :i* is probably little conc]n$ 9 ! reactions ( ! complex z su*4 ,! names silv]-ammonia ion & silv]-ammonia nitrate s\nd badly & d n emphasize ! relation to ammonium1 potassium1 sodium & simil> positive ions & _! salts4 ,! t]m ammonium is1 = ! reasons giv51 us$ "h 9 a g5]ic s5se = all complex ions ( ammonia ) simple metal ions 7su* z ,h1 ,ag1 ,cu#b1 ,zn#b etc471 & ! numb] ( ammonia molecules1 ent]+ into ! composition ( a complex ion1 is n indicat$ 9 ! names4 ,a simil> nom5clature has long be5 9 vogue1 & has work$ well1 = ! complex ions ( metal ions ) ! cyanide-ion 7see bel[74 ,we speak ( f]rocyanide1 ,fe7,,cn7#fd1 arg5ticyanide1 ,ag7,,cn7#b & ,ag#b7;,,cn7#cb1 etc41 )\t indicat+ ! numb] ( cyanide gr\ps1 ,,cn1 9 ! complex1 & we use ! same g5]ic end+ cyanide z is us$ to designate ! simple cyanide ion1 e4g4 to designate ! ion =m$ f potassium cyanide1 ,,kcn ,k ,,cn4 #dbf ,! hydroxide-ion appe>s ) ! same coeffici5t1 #a1 on bo? sides ( ! equilibrium equation & ne$ n be includ$ 9 ! ma!matical /atem5t2 x w\ld appe> z a factor 9 bo? t]ms ( ! ratio giv5 & w\ld cancel out4 #dbg ,bodlnd] & ,fittig1 ,z4 phys4 ,*em41 #ci1 #fjb 7#aijc74 #dbh ,bonsdorff1 ,b]4 d4 *em4 ,ges41 #cf1 #bcbd 7#aijc74 #dbi ,x is also frequ5tly call$ ! dissociation con/ant ( ! complex ion1 indicat+ ! t5d5cy ( ! complex ion to dissociate into its compon5ts4 #dcj ,two indep5d5t exp]im5tal me?ods 7 us$ & gave concordant results--"o hav+ z its basis ! solubility ( silv] salts 7*loride1 bromide71 ! o!r ! electrolytic pot5tials ( silv] aga9/ ammoniacal silv] solutions 7see ,*ap4 ,,xv74 #dca ,bull4 de la ,soc4 ,*im4 de ,p>is1 7#c71 #ac1 #chf 7#ahie74 #dcb ,we may consid] ! salt to be ioniz$ to ab\t ! same ext5t z ammonium or potassium nitrate 9 #j4je mol> solutions1 or1 approximately1 #hg4 ,if we call x ! conc5tration ( silv]-ion1 =m$ by ! decomposition ( ! silv]-ammonium-ion1 !n #b x is ! conc5tration ( ! free ammonia1 & 7#j4je #j4hg x7 is ! conc5tration ( ! complex ion4 ,s9ce x is a small numb] 9 comp>ison ) #j4jdce1 we may write1 ) suffici5t accuracy = our purposes1 ,,nh#cb ,ag _/ 7,,nh#c7b;,ag 7#b x7#b x _/ #j4jdce #f4h;,e#h4 ,!n1 x ,ag #j4jjji4 #dcc ,kohlraus* & ,holborn1 loc4 cit41 p4 #bjb4 #dcd ,! dilution ( ! silv]-ammonium nitrate 7#aj c4c4 to #aa c4c47 & ! decrease 9 ionization due to ! add$ salt r$uce ! conc5tration ( silv]-ion f #j4jjji to #j4jjjhe4 ,ag7,,nh#c7b 7#j4je #aj _/ #aa7 #j4h #j4jcfd & #d x#c #f4h;,e#h #j4jcfd 7see footnote1 p4 #bbj74 ,!n x ,ag #j4jjjhe4 #dce ,?iel 7cf4 ,bodlnd] & ,fittig1 loc4 cit474 ,! solubility giv5 9 ! table at ! end ( ! laboratory manual ref]s to #ah4 ,! con/ant = ! complex ion 0 det]m9$ at #be4 #dcf ,! comb9$ conc5tration ( ! salts is #j4jee & _! degree ( ionization may be tak5 z #hg1 ! same z ! degree ( ionization ( #j4je to #j4jf mol> ,,kno#c4 ,!n ,cl 7#j4a #a _/ #aa7 #j4hg #j4jjh4 ,ag7,,nh#c7b 7#j4je #aj _/ #aa7 #j4hg #j4jd & x ,ag #j4jjjhi 7see ! me?od ( calculation 9 ! footnote1 p4 #bbj74 #dcg ,! /rong solution ( ammonia is us$ 9 ord] to avoid unnecess>y dilution1 & 9 ! exp]im5t1 describ$ bel[1 ! dilution ( ! liquids by ! add$ ammonia is consid]$ negligible4 #dch ,! foll[+ solubilities h be5 det]m9$ at #be3 ,ag ,cl #b;,e#aj2 ,ag #a4d;,e#e4 ,ag ,i #a;,e#ae2 ,ag #a;,e#h4 ,ag#b ,s#b #d;,e#ej2 ,ag #d4c;,e#ag4 #dci #ajj c4c4 mol> ammonia dissolves at #be only #j4f milligram ( silv] iodide 7,bodlnd]1 loc4 cit41 p4 #fjf74 #ddj ,fres5ius1 ,qualitative ,analysis1 p4 #cgh4 #dda ,9 reg>d to ,cu7,,nh#c7db see ,locke & ,=ssall1 ,am4 ,*em4 ,j41 #ca1 #bfh1 #big 7#aijd71 & ,dawson1 ,j4 ,*em4 ,soc4 7,london71 #hi1 #afgd 7#aijf74 #ddb ,eul]1 ,b]4 d4 *em4 ,ges41 #cf1 #cdjc 7#aijc74 #ddc ,see footnote1 p4 #bab4 #ddd ,see pp4 #afe1 #baj & #bac4 #dde ,! acid ,h,ag7,,cn7#b1 correspond+ to ! salt1 is cry/allizable & is a /rong acid4 ,x is l>gely decompos$1 by wat]1 into silv] cyanide & hydrocyanic acid4 #ddf ,see ! exp]im5ts describ$ on pp4 #de & #hi4 #ddg ,9 solutions conta9+ an excess ( potassium cyanide great] ?an #j4je mol>1 ! salt ,k#b;,ag7,,cn7#c is =m$4 ,! dissociation or in/ability con/ant = ! complex ion ,ag7,,cn7#cb is #a;,e#bb4 #ddh ,z4 anorg4 ,*em41 #ci1 #bbb 7#aijd74 #ddi ,! solubility-product con/ant = silv] *loride at #be is #b;,e#aj4 ,if ! conc5tration ( *loride-ion be made #a4j by ! addition ( potassium *loride to a #j4je mol> solution ( ,k,ag7,,cn7#b1 !n ! conc5tration ( silv]-ion1 necess>y = ! precipitation ( ! *loride1 w\ld be ,k,s4,p4 _/ ,cl #b;,e#aj gram-ion4 ,neglect+ ! fact t ! complex salt is n completely ioniz$ & putt+ ,ag7,,cn7#b #j4je1 & call+ x ! conc5tration ( ! cyanide-ion j necess>y to prev5t ! precipitation ( ! *loride1 we h3 ,ag ,,cn#b _/ ,ag7,,cn7#b #b;,e#aj x#b _/ #j4je #ajba4 ,we f9d x #e;,e#g mole1 or approximately #j4jc milligram potassium cyanide 7cyanide-ion7 p] lit]4 ,?is m9ute quantity ( free cyanide1 if n orig9ally pres5t 9 ! solution us$1 w\ld be =m$ by ! lib]ation ( potassium cyanide f ! complex 7accord+ to ,k,ag7,,cn7#b ,k,cl ,ag,cl #b ,,kcn7 z soon z #b4e;,e#g mole1 or #j4jcf milligram1 ( silv] *loride p] lit] h be5 =m$1 a quantity too small to be p]ceptible4 ,:5 potassium cyanide is add$ to a silv] nitrate solution1 ! precipitate =m$ is f\nd to be silv] arg5ticyanide1 ,ag,ag7,,cn7#b1 ! silv] salt ( ! extremely /able complex1 r ?an ! simple salt1 silv] cyanide1 ,ag,c,n cf4 ,bodlnd]1 ,z4 anorg4 ,*em41 #ci1 #bbc 7#aijd74 ,ag,ag7,,cn7#b is ev5 less soluble ?an silv] *loride1 ! solubility-product con/ant = ,ag ,ag7,,cn7#b be+ #b4be;,e#ab4 ,an excess ( only #b;,e#f mole1 or ab\t #j4ae milligram1 ( potassium cyanide 7cyanide-ion7 p] lit] is suffici5t to prev5t ! precipitation ( silv] cyanide 7silv] arg5ticyanide7 f a #j4a mol> solution ( ,k,ag7,,cn7#b1 &1 conv]sely1 at lea/ ?is m9ute excess ( potassium cyanide is us$ 9 ! prep>ation ( a cle> #j4a mol> solution ( ,k,ag7,,cn7#b1 by ! addition ( potassium cyanide to silv] nitrate1 until ! silv] cyanide1 fir/ precipitat$1 is j r$issolv$ 7,bodlnd]1 loc4 cit474 ,?is excess1 z j expla9$1 is m ?an suffici5t to prev5t ! precipitation ( silv] *loride f ! cyanide solution1 ev5 by a l>ge excess ( potassium or sodium *loride4 ,unless "o takes into acc\nt1 9 ! mann] indicat$1 ?is m>k$ influ5ce ( a m9ute excess ( cyanide-ion 9 decid$ly r$uc+ ! conc5tration ( silv]-ion 9 ^! solutions1 "o c\ld be l$1 wrongly1 to inf] f ! value ( ! in/ability con/ant ( ! complex ion & t ( ! solubility-product con/ant ( silv] *loride1 t silv] *loride %\ld /ill be precipitat$ by ! addition ( sodium *loride to a solution ( ,k,ag7,,cn7#b4 #dej ,= ?is reason potassium cyanide is an excell5t cleans+ ag5t = /a9$ silv]w>e 7sulphide /a9s71 &1 s9ce x is an int5se poison1 clean+ p[d]s %\ld be exam9$ = x4 #dea ,= ! quantitative relations see ,lucas1 ,z4 anorg4 ,*em41 #da1 #aib 7#aijd74 #deb ,see ,bodla5d]1 ,z4 phys4 ,*em41 #ci1 #eig 7#aijb72 ,b]4 d4 *em4 ,ges41 #cf1 #cicc 7#aijc74 #dec ,potassium cyanide is a p[]ful r$uc+ ag5t 7see p4 #hi7 & is readily oxidiz$ to potassium cyanate4 ,! action1 presumably1 takes ! foll[+ c\rse 7see ,*apt]s ,,xiv & ,,xv73 #b ,cu#b #d ,,ho ,,knc #b ,cu #d ,,ho ,,knc#b #b ,cu #b ,,ho ,,knco ,h#b,o4 #ded ,put ,cu x1 & ,,cn #c x1 &1 neglect+ ! degree ( ionization1 ,cu7,,cn7#cb #j4a1 x be+ s small t x ne$ n be subtract$ f #j4a4 ,!n x 7#c x7#c #j4a #j4e;,e#bg1 & x #c4g;,e#h4 #dee ,treadwell & ,girsewald1 ,z4 anorg4 ,*em41 #ch1 #ib 7#aijd74 #def ,eul]1 ,b]4 d4 *em4 ,ges41 #cf1 #cdjd 7#aijc74 #deg ,putt+ ,cd#b y1 we h y 7#d y7#d #j4a;,e#ag1 & y #h;,e#e4 ,9 view ( ! values ( ! con/ants1 a small excess ( potassium cyanide w h a mu* small] suppress+ effect on ! cadmium-ion ?an on ! cupr\s-ion4 ,= ! excess ,,cn #j4ja1 ,cu #e;,e#bc1 ,cd#b #ajaj z comp>$ ) ,cu #d;,e#h 9 a #j4a mol> solution ( ! salt ,k#c;,cu7,,cn7#c1 & ) ,cd#b #h;,e#e 9 a #j4a mol> solution ( ,k#b;,cd7,,cn7#d4 #deh ,brom9e wat] is a conv5i5t ag5t = oxidiz+ cobalt\s to cobaltic ions 7see ,*apt] ,,xv74 #dei ,! heavy arr[s ,see ,transcrib]'s ,note indicate ! ma9 c\rse ! rev]sible actions take1 "u ! influ5ce ( ! reag5ts us$4 ,s9ce ! oxidation ( nickel-ion by brom9e is accompli%$ only aft] ! brom9e has oxidiz$ any excess ( cyanide us$--potassium cyanide is a p[]ful r$uc+ ag5t 7p4 #hi7--! addition ( cyanide1 beyond a v small excess1 mu/ be avoid$ 7see laboratory in/ructions74 #dfj ,e4g4 = ! precipitation ( silv]1 copp]1 nickel1 cobalt & c]ta9 o!r metals f cyanide solutions2 cf4 ,edg> ,f4 ,smi?1 ,electro-,analysis 7#aijg74 #dfa ,z4 phys4 ,*em41 #dc1 #gje 7#aijc74 ,vide also ,hab]1 ,z4 ,elektro*em41 #aa1 #hdg 7#aije74 #dfb #b ,fe#b ,hg#b #b ,fe#c ,hg 4 ,if ! treatm5t ) m]curic oxide is c>ri$ to completion ! f9al products ( ! reaction are f]ric hydroxide1 m]curic cyanide1 m]cury & potassium hydroxide 7,rose1 ,z4 anal4 ,*em41 #a1 #cjj 7#ahfb773 #b ,k#d;,fe7,,cn7#f #g ,hg,o #g ,h#b,o #c ,hg,hg7,,cn7#d #h ,,koh #b ,fe7,,oh7#c ,hg #dfc ,bodla5d]1 loc4 cit4 #dfd ,! solubility-product con/ant ( silv] sulphide at #be is #j4e;,e#ea2 = ,s#b #j4h;,e#e 7p4 #bjb71 we w\ld h 9 ! pres5t case ,ag#b ,s#b #b;,e#df1 :i* is great] ?an ! con/ant4 ,vide quantitative data by ,lucas1 loc4 cit4 #dfe ,z4 f4 ,elektro*em41 #aj1 #dcc & #ggc 7#aijd74 #dff ,see footnote #d1 p4 #bbe4 #dfg ,o/wald1 ,allgem4 ,*emie1 ,vol4 ,,ii1 "p #a1 p4 #hha 7#ahic74 #dfh ,hab]1 loc4 cit4 #dfi ,!n ,t,decomposition #ajd #ajbb #ajah seconds1 &1 s9ce !re are #c4ae;,e#g seconds 9 a ye>1 ,t,decomposition #c;,e#aj ye>s4 #dgj ,see p4 #db4 #dga ,s9ce !re are /ill small] in/ability con/ants ?an t ( ! arg5ticyanide-ion 7e4g4 = ! gold-cyanide-ion ! con/ant is #a _/ #ajbh71 !re is a l>ge m>g9 ( safety = ! plausibility ( ,hab]'s argum5t4 ,= full details1 8 articles 7loc4 cit471 & ! discussion 7by ,abegg1 ,bodla5d]1 ,danneel1 ibid47 ar\s$ by !m %\ld be consult$4 #dgb ,see ,le ,blanc & ,s*ick1 ,z4 phys4 ,*em41 #df1 #bac 7#aijc71 on measurem5ts ( ! spe$ ( ionic actions4 ,! values obta9$ agree1 9 g5]al1 ) ,hab]'s cont5tion4 #dgc ,! conc5trations ( silv]-ion are l>ge1 9 comp>ison ) ^? 9 cyanide solution1 & ! action is1 mo/ likely1 ess5tially an ionic "o2 b ! argum5t applies ) equal =ce to cyanide sy/ems4 #dgd ,loc4 cit4 #dge ,an equilibrium con/ant1 z we h se51 is a ratio ( velocity con/ants ( balanc$ reactions 7pp4 #id1 #bcc7 & involves !re=e at lea/ two unkn[n velocity con/ants4 ,by det]m9+ ! actual rate ( *ange ) kn[n conc5trations ( react+ compon5ts1 i4e4 by det]m9+ ! velocity con/ants !mselves1 r ?an _! ratio1 a def9ite conclusion z to ! me*anism or pa? ( a giv5 reaction c (t5 be rea*$ 7see p4 #hj74 #dgf ,proce$+s ,am]4 ,academy1 #ahib4 #dgg ,9 ! abs5ce ( any add$ cyanide1 x comb9es ) itself4 ,silv] cyanide1 accord+ to ,bodlnd]'s results1 is1 9 saturat$ solutions1 *iefly 7,ag,c,n7#b or ,ag,ag7,,cn7#b1 i4e4 ,ag--,n,c,c,n--,ag4 #dgh ,see p4 #bbe1 footnote #d4 #dgi ,w]n] has develop$ q a diff]5t !ory ( ! /ructure ( complex ions4 7,cf4 ,n]n/1 ,!oretical ,*emi/ry1 p4 #cgd 7#aijd747 #dhj ,%]rill1 ,z4 phys4 ,*em41 #dc1 #gba 7#aijc74 #dha ,9 ,nessl]'s reag5t1 ,fres5ius' ,qualitative ,analysis1 p4 #ada4 #dhb ,cf4 ,rems51 ,am4 ,*em4 ,j41 #aa1 #bia 7#ahii72 #ad1 #ha 7#ahib7 7,/ud474 #dhc ,= in/ance1 = ars5i\s acid we h #c ,h ,as,o#cc ,h#c;,as,o#c ,z#c #c ,,ho &1 !re=e1 ,z#c ,,ho#c _/ 7,as,o#cc ,,ho#c7 k#a4 ,s9ce ,h k,,hoh _/ ,,ho 7p4 #agf71 we h fur!r1 ,z#c ,,ho#f _/ ,as,o#cc k#b4 ,& s9ce we may d]ive ! relation ,,ho#b k#c ,o#b1 by consid]+ ! prim>y & ! second>y ionization ( wat] 7see pp4 #bdf1 #bgh71 we h1 f9ally1 ,z#c ,o#bc _/ ,as,o#cc ,k4 ,! con/ants = ! prim>y & ! second>y ionization ( wat] are includ$ 9 ! value ( ,k4 #dhd ,fitzg]ald & ,lapwor?1 ,j4 ,*em4 ,soc4 7,london71 #ic1 #bafc 7#aijh72 ,lapwor?1 ibid41 #bahg4 ,vide also ,frankl9 on ! *>act]i/ics ( ! ,,nh#d ion 9 liquid ammonia1 ,am4 ,*em4 ,j41 #bc1 #cje 7#aijj74 #dhe ,see ! laboratory in/ructions1 9 reg>d to ! precautions us$1 to avoid errors f ?is s\rce4 #dhf ,on ! o!r h&1 colloidal organic sub/ances1 su* z case91 glue or album51 int]f]e ) ! precipitation ( ev5 ! mo/ insoluble sulphides1 by produc+ colloidal susp5sions ( ! latt] 7see ,*ap4 ,,vii2 cf4 ,mll]1 ,allgeme9e ,*emie d] ,kolloide1 p4 #ef 7#aijg774 #dhg ,9 alcohols ! hydroxide gr\p is held by a c>bon atom1 ^: rema9+ val5ces are satisfi$ by hydrog5 or c>bon atoms1 z 9 ord9>y or e?yl alcohol1 ,h#c;,c--,,*#b7,,oh74 #dhh ,k/]1 ,z4 ,elektro*em41 #d1 #aag 7#ahig74 #dhi ,! mo/ common organic acids conta9 ! acid gr\p --,,co7,,oh71 z 9 acetic acid1 ,,*#c;,,co7,,oh74 ,! hydroxide gr\p ,,oh ( ! alcohols1 e4g4 9 ,,*#c;,,*#b7,,oh71 is /ill f\nd 9 ^! organic acids1 b its t5d5cy to =m hydrog5-ion is v mu* increas$ by ! replacem5t ( two hydrog5 atoms ( ! alcohols by ! oxyg5 atom1 z f\nd 9 ! acids4 ,to a c]ta9 degree1 ! prop]ties ( ! alcohol hydroxide are ma9ta9$ 9 ! prop]ties %[n by ! acid hydroxide gr\p4 ,?us1 ! organic acids1 on ! :ole1 are /ill r weak acids1 & _! salts1 9 _m in/ances1 are appreciably less ionizable ?an ! salts ( /rong inorganic acids4 ,! organic acids1 fur!r1 may comb9e1 to a c]ta9 ext5t1 ) wat] & ?us =m hydrates 7e4g4 ,,*#c;,,cooh ,h#b,o ,,*#c;,c7,,oh7#c7 conta9+ a numb] ( hydroxide gr\ps3 ! second & ?ird hydroxide gr\ps mu/ h a v mu* small] t5d5cy to =m hydrog5 ions & ionizable salts1 ?an has ! fir/ hydroxide gr\p 7p4 #ajb71 & ! =m]1 ?us %[1 m ne>ly1 ! behavior ( alcoholic hydroxide gr\ps4 ,f9ally1 organic acids also %[ a t5d5cy to comb9e ) !mselves1 =m+ complex acids 7e4g41 7,,*#c;,,cooh7#b or ,,*#c;,c7,,oh7#b,,ooc*#c71 f :i* complex salts may be d]iv$1 :i* may be little ionizable4 ,! p[] ( ! organic acids to =m complex ions--:i* !y %>e ) _m inorganic acids--is mo/ likely intimately connect$ ) ! relations describ$4 #dij ,lead acetate1 itself1 is less ioniz$ ?an mo/ salts & ?is prop]ty contributes to ! solubility ( lead sulphate 9 acetate solutions4 7,cf4 ,noyes & ,bray1 loc4 cit47 #dia ,on p4 #bca1 ! same effect is discuss$1 9 detail1 9 connection ) ! f]ricyanide-ion4 p#bdb ,,*apt] ,,xiii ,,! ,,ars5ic ,,gr\p4 ,,sulpho-,,acids ,,& ,,sulpho-,,salts ,! analytical gr\ps1 :i* we h h]et(ore discuss$1 conta9 elem5ts1 ^: oxides are prem95tly base-=m+4 ,! me?ods ( sep>ation ( ^! gr\ps1 f ea* o!r1 involve1 prim>ily1 physical#dib diff]5ces betwe5 ! gr\ps--9 ! matt] ( ! relative insolubility ( analog\s salts4 ,?us1 b>ium1 /rontium & calcium c>bonates are precipitat$1 & sep>at$ f ! alkalies1 by means ( ammonium c>bonate1 n because ! alkalies d n =m c>bonates :5 _! salts1 9 solution1 are treat$ ) ammonium c>bonate1 b :olly because b>ium1 /rontium & calcium c>bonates are v difficultly1 ! alkali c>bonates easily1 soluble 9 wat]4 ,! hydroxides ( ! alum9ium gr\p & ! sulphides ( ! z9c gr\p are less soluble ?an ! hydroxides & sulphides ( ! alkal9e e>?s & alkalies4 ,! sulphides ( ! copp] & ! ars5ic gr\ps1 aga91 are /ill less soluble ?an ! sulphides ( ! z9c gr\p1 & ?us ! =m] may be precipitat$ by hydrog5 sulphide1 ev5 :5 its precipitat+ p[] is r$uc$ by ! suppression ( its sulphide 7& hydrosulphide7 ions by ! addition ( a /rong acid4 ,on ! o!r h&1 ! sep>ation ( ! ars5ic gr\p 7ars5ic1 antimony1 t91 gold & plat9um7 f ! copp] gr\p1 ) :i* x is precipitat$ by hydrog5 sulphide f acid solutions1 dep5ds1 ess5tially1 on a *emical diff]5ce betwe5 ! gr\ps4 ,! oxides1 especially ! high] oxides1 ( ! ars5ic gr\p1 are prem95tly acid-=m+2 ! high] oxides =m su* acids z ars5ic acid1 ,h#c;,as,o#d1 antimonic acid1 ,h#c,sb,o#d1 /annic acid1 ,h#b,sn,o#c1 plat9ic acid1 ,h#b,pt,o#c1 & auric acid1 ,h,au,o#b4 ,^! p#bdc hydroxides are1 h[ev]1 all m or less weakly basic 9 "* z well4 ,! hydroxides ( ! l[] oxides ( ! metals are1 z "o mu/ expect1 mu* m /rongly basic1 b mo/ ( !m--ars5i\s1 antimon\s & /ann\s hydroxides--/ill %[ suffici5t acid "* to be di/9ctly amphot]ic 9 behavior4 ,b1 ) ! exception ( ars5i\s acid1 ! basic ionization ( ! hydroxides ( ! l[] oxides is m pron\nc$ ?an _! acid ionization4 ,! basic ionization ( ! hydroxides ( _! l[] & high] oxides br+s ^! elem5ts into ! plan ( analysis = ! metal or positive ions 9 sy/ematic analysis4 ,9 ! pres5ce ( hydro*loric acid !y =m *lorides1 :i* yield positive ions 9 suffici5t quantity#dic to all[ _! extremely insoluble sulphides to be precipitat$ by hydrog5 sulphide 9 acid solution1 toge!r ) !1 likewise1 v insoluble sulphides ( ! copp] gr\p4 ,! acid-=m+ prop]ties ( ! oxides ( ! ars5ic gr\p are ma9ta9$ 9 _! sulphides4 ,aga91 ?is is especially evid5t 9 ! high] sulphides4 ,! elem5t sulphur is sub/itut$ = ! closely relat$ elem5t oxyg5 )\t any pr(\nd *ange 9 ! *emical behavior ( ! comp\nds4 ,advantage is tak5 ( ?is acid-=m+ p[] to sep>ate ! sulphides ( ! ars5ic gr\p f ! sulphides ( ! copp] gr\p1 :i* ei!r are n acid-=m+ at all1 or exhibit ?is prop]ty only to a v slight degree4#did ,sulpho-,salts4--,! simil>ity 9 ! behavior ( oxyg5 & sulphur d]ivatives1 9 ?is respect1 is g5]al & is n re/rict$ to ! metal sulphides we are discuss+4 ,= in/ance1 ! acid-=m+ p[] ( c>bon dioxide is %[n also by c>bon disulphide1 ! correspond+ sulphur d]ivative ( c>bon4 ,j z ! =m] comb9es ) potassium hydroxide to =m a c>bonate1 s c>bon disulphide dissolves 9 solutions ( potassium hydrosulphide & potassium sulphide to =m potassium sulpho-c>bonate3 ,,co#b #b ,,koh ,k#b;,,co#c ,h#b,o4 7#a7 ,,cs#b #b ,,k% ,k#b;,,cs#c ,h#b,s4 7#b7 ,,cs#b ,k#b,s ,k#b;,,cs#c4 7#c7 p#bdd ,! high] sulphides ( ! ars5ic gr\p1 & ars5i\s & antimoni\s sulphides among ! l[] ones1 comb9e ) ! alkali sulphides to =m soluble alkali salts ( sulpho-acids1 9 ! same way z c>bon bisulphide does4 ,9 ! case ( ars5i\s sulphide1 = in/ance1 we h ! action ,z#b,s#c 7,,nh#d7b,s #b ,,nh#d;,as,s#b4 7#d7 ,! salt1 ammonium sulph>s5ite1 is ioniz$ z foll[s3 ,,nh#d;,as,s#b ,,nh#d ,as,s#b4 ,sulpho-,acids4--,! free sulpho-acids are lib]at$1 f _! salts1 by any /rong] acid1 su* z hydro*loric acid2 ! acids are extremely un/able & rev]t rapidly to ! sulphides1 f :i* _! salts 7 orig9ally obta9$4 ,we h1 = in/ance1 #b ,h,as,s#b ,z#b ,s#c ,h#b,s 4 ,?is in/ability ( ! sulpho-acids is entirely analog\s to ! in/ability ( ! metal hydrosulphides 7p4 #bjc7 & to ! in/ability ( c]ta9 oxyg5 acids1 notably ( c>bonic acid4 ,sulpho-c>bonic acid1 ,h#b;,,cs#c1 is ! be/-kn[n free acid ( ?is type4 ,x may be precipitat$1 undecompos$1 z an oil1 & its gradual decomposition into hydrog5 sulphide & c>bon disulphide may be obs]v$4 ,sulpho-,bases4--,s9ce "o meets1 9 ?is gr\p1 sulpho-acids & sulpho-salts1 correspond+ to ! oxyg5 acids & _! salts1 "o is naturally l$ to inquire1#die :e!r ! ?ird great class ( oxyg5 comp\nds is n f\nd duplicat$ among sulphur comp\nds1 :e!r sulpho-bases1 z well z sulpho-acids & salts1 are kn[n4 ,"o w\ld look = su* bases1 ) ! mo/ pron\nc$ basic "*1 among ! comp\nds obta9$ by ! sub/itution ( sulphur = oxyg5 9 ! /ronge/ oxyg5 bases4 ,to a c]ta9 ext5t potassium & sodium hydrosulphides & sulphides %[1 9 fact1 prop]ties1 :i* are ak9 to ^? fundam5tally *>act]i/ic ( ord9>y bases4 ,!y comb9e ) acid sulphides to =m sulpho-salts1 z ! oxyg5 bases comb9e ) acid oxides4 ,to a v consid]able ext5t !y neutralize all b ! v weake/ acids2 hydrog5 sulphide1 itself a v weak acid1 is driv5 out ( its salts by all /rong] acids1 & ! latt] are almo/ completely neutraliz$4 ,= in/ance1 we h3 p#bde ,,koh ,h,cl ,k,cl ,h#b,o1 & ,,k% ,h,cl ,k,cl ,h#b,s & ,k#b,s #b ,h,cl #b ,k,cl ,h#b,s4 ,! conc5tration ( ! hydrog5-ion is r$uc$ mo/ decid$ly 9 ea* ( ^! reactions4 ,,exp4--,a solution ( potassium hydrosulphide is saturat$ ) hydrog5 sulphide1 9 ord] to prev5t hydrolysis & ! =mation ( potassium hydroxide#dif 7p4 #ahj71 z f> z possible1 & ! solution is add$ to an acid 7hydro*loric7 solution ( me?yl orange2#dig ! acid color is *ang$ to orange1 z a result ( ! almo/ complete neutralization ( ! acid4 ,! potassium hydrosulphide 7! hydrosulphide-ion ,,hs7 neutralizes ! hydrog5-ion 7( hydro*loric acid71 t conv]ts me?yl orange into its p9k salt1 & hydrog5 sulphide is =m$1 :i* is too weak an acid to affect ! color ( ! indicator 7p4 #gi74 ,! objection t potassium sulphide & hydrosulphide are salts1 ! salts ( hydrog5 sulphide1 might be rais$ aga9/ ! conception ( _! possess+ a c]ta9 measure ( basic functions2 b ! common oxyg5 base1 potassium hydroxide1 is also a salt1 ! salt ( a /ill weak] acid1 wat]4 ,inde$1 ! *>act]i/ic prop]ties ( ord9>y bases are due ess5tially to ! fact1 t !y are ! m or less readily ionizable salts ( an extremely weak acid1 wat]1 & ^! prop]ties may well be duplicat$ by salts ( o!r weak acids1 duplicat$ 9 a v mu* weak] way1 9 proportion z ! acids are /rong] ?an wat]4 ,! diff]5ce is1 !n1 really "o ( degree & n ( k9d4#dih ,ow+ to ! fact t hydrog5 sulphide is a mu* /rong] acid ?an wat]1 ! action ( potassium hydrosulphide on an acid sulphide1 l c>bon disulphide 7equation 7#b71 p4 #bdc71 is rev]s$ to a correspond+ly great] degree ?an ! action ( potassium hydroxide on c>bon dioxide#dii 7equation 7#a71 p4 #bdc74 ,! dissociation con/ant = ! second>y ionization ( hydrog5 sulphide 7,,hs ,h ,s#b7 is v mu* small] ?an ! con/ant = ! prim>y ionization 7,,hs is a mu* weak] acid ?an ,,h%71 & s we f9d t a sulphide l ,k#b,s exhibits v mu* /rong] basic functions ?an d ! hydrosulphides1 z1 = in/ance1 9 =m+ salts ) acid-=m+ sulphides p#bdf 7equation 7#c71 p4 #bdc7 & 9 neutraliz+ acids4 ,!re c be no "q t1 if we c\ld h an aque\s solution ( potassium oxide1 ,k#b,o1 x w\ld %[1 simil>ly1 ! *>act]i/ic actions ( /rong bases ev5 m p[]fully ?an ! hydroxide1 ,,koh2 = in/ance1 9 act+ on acid-=m+ oxides 7equation 7#a71 p4 #bdc71 9 neutraliz+ acids1 9 saponify+ e/]s 7p4 #ha71 & s =?4 ,x is1 9 fact1 on acc\nt ( ?is prop]ty1 t potassium oxide is decompos$ by wat]4 ,x is a salt involv+ ! second>y ionization ( wat]1 7,,ho ,h ,o#b71 :i* has a mu* small] dissociation con/ant ev5 ?an ! prim>y ionization 7,h#b,o ,h ,,ho74 ,! oxide1 ,k#b,o1 is decompos$ by neutraliz+ hydrog5 ions =m$ by ! prim>y ionization ( wat]4 ,we h #b ,k ,o#b ,h ,,ho #b ,k #b ,,ho1 :i* is entirely analog\s1 9 pr9ciple1 to ,k ,,ho ,h ,cl ,k ,cl ,,hoh4 ,sulphoxy-,salts4--,! close relations betwe5 ! oxyg5 & ! sulphur s]ies are se5 also 9 ! fact t an oxyg5 base may be comb9$ ) an acid sulphide1 & vice v]sa2 ars5i\s sulphide1 = in/ance1 dissolves ev5 9 ! solution ( s weak a base z ammonium hydroxide 7exp474 ,! salts produc$ by ?is cross+ are usually hybrid salts1 p>tly sulpho-1 p>tly oxyg5-salts4 ,!re is1 = in/ance1 a s]ies ( ars5iates1#ejj ,me#c;,as,o#d1 ,me#c;,as,s,o#c1 ,me#c;,as,s#b,o#b1 ,me#c;,as,s#c,o & ,me#c;,as,s#d4 ,9 analytical "w ! pure types are ord9>ily utiliz$1 r ?an ! mix$ types4 ,complex ,sulphide ,ions4--,! ions ( ! sulpho-acids1 l ! ions ( oxyg5-acids 7p4 #bch71 may also be treat$ z complex ions--( ! positive metal ions & ! sulphide-ion1 ,s#b4 ,ammonium sulphide comb9es ) /annic sulphide1 =m+ ammonium sulpho/annate3 ,sn,s#b 7,,nh#d7b,s 7,,nh#d7b,sn,s#c4 ,if ! action is consid]$ to be ! result ( int]actions ( ! ions ( /annic & ammonium sulphides1 we c resolve ! equation into ! foll[+ "o3 ,sn#d #b ,s#b #b ,,nh#d ,s#b #b ,,nh#d ,sn,s#cb4 ,! ammonium-ion1 appe>+ ) ! same coeffici5t on bo? sides ( ! la/ equation1 evid5tly takes no direct "p 9 ! action & we h m simply3 ,sn#d #c ,s#b ,sn,s#cb4 ,= ! condition ( equilibrium betwe5 ! complex & its compon5ts we h3#ejaejb ,sn#d ,s#bc _/ ,sn,s#cb ,k4 p#bdg ,sulphurization ( ,sulphides4--,s9ce ! solubility ( ! ars5ic gr\p ( sulphides 9 ammonium sulphide solution--! reag5t commonly us$ 9 analysis--dep5ds on ! =mation ( soluble sulpho-salts1 due consid]ation mu/ be tak5 ( ! fact t "s ( ! l[] sulphides--notably /ann\s1 aur\s & plat9\s sulphides--d n possess acid-=m+ prop]ties 9 any m>k$ degree2 ev5 antimon\s sulphide is soluble only 9 a consid]able excess ( ammonium sulphide4 ,9 ord]1 !n1 to insure a m complete sep>ation ( ! ars5ic f ! copp] gr\p1 precautions are tak5 to sulphurize ! l[] sulphides to high]1 /rong] acid-=m+1 sulphides1 9 ! c\rse ( ! sep>ation4 ,= ?is purpose s-call$ yell[ ammonium sulphide1 conta9+ p]sulphides ( ammonium1 7,,nh#d7b,s#b1 etc41 is us$ 9 place ( a solution ( ammonium sulphide & ammonium hydrosulphide4 ,/ann\s sulphide1 = in/ance1 is dissolv$ by ! reag5t z ammonium sulpho/annate3 ,sn,s 7,,nh#d7b,s#b 7,,nh#d7b,sn,s#c4 ,behavior ( ,ars5ic ,acid t[>d ,hydrog5 ,sulphide4--,9 conclusion1 special consid]ation mu/ /ill be giv5 to ! behavior ( ars5ic acid1 ,h#c;,as,o#d4 ,z its "n indicates1 x is an acid1 &1 9 fact1 a r /rong acid1 ( ! ord] ( /r5g?#ejc ( phosphoric acid1 ,h#c,,po#d1 :i* x resembles 9 composition & 9 _m ( its prop]ties4 ,z a /rong acid1 ars5ic acid1 :5 x is ioniz$1 yields *iefly negative ars5iate ions1 ,h#b;,as,o#d1 ,h,as,o#db & ,as,o#dc4 ,any basic prop]ties1 :i* x may &1 mo/ likely1 does possess1 mu/ be extremely weak4 ,x is1 !re=e1 n surpris+ to f9d t unusual difficulties are exp]i5c$ 9 precipitat+ ars5ic sulphide1 by hydrog5 sulphide1 f ars5iate p#bdh solutions1 9 z mu* z hydrog5 sulphide is an ag5t = ! precipitation ( ! sulphides ( cations4 ,ars5i\s acid1 ! hydroxide ( ! l[] oxide1 on ! o!r h&1 is a mu* weak] acid & %[s m pron\nc$ basic 7amphot]ic7 prop]ties1 & ars5ic trisulphide is precipitat$1 )\t difficulty1 f solutions ( ars5i\s acid 9 hydro*loric acid4 ,we h3 #b ,z#c #c ,s#b ,z#b,s#c 4 ,:5 ars5ic acid is r$uc$ to ars5i\s acid by sulphur\s acid1 by iodides 7see ,*ap4 ,,xvi7 or by hydrog5 sulphide 7see bel[71 no fur!r difficulty 9 precipitat+ a sulphide 7,z#b,s#c7 is exp]i5c$4 ,:5 a solution ( ars5ic acid1 conta9+ ! usual small am\nt ( hydro*loric acid 7#j4c mol>71 is treat$ ) hydrog5 sulphide at ord9>y temp]atures1 ! foll[+ ?ree reactions take place1 b exce$+ly sl[ly3 #b ,h#c;,as,o#d #e ,h#b,s ,z#b,s#e #h ,h#b,o 7#a7ejd ,h#c;,as,o#d ,h#b,s ,h#c;,as,o#c ,s ,h#b,o 7#b7eje #b ,h#c;,as,o#c #f ,h,cl #c ,h#b,s #b ,as,cl#c #c ,h#b,o #c ,h#b,s ,z#b,s#c #f ,h,cl #c ,h#b,o 7#c7 ,ev5 9 ! pres5ce ( a consid]able am\nt ( ars5ic acid1 precipitation1 ei!r ( ! trisulphide or ( ! p5tasulphide1 may n occur = "s "t1 &1 unless "o takes acc\nt ( t fact1 ! dang]\s elem5t1 ars5ic1 w\ld easily be ov]look$4 ,heat accel]ates bo? ! precipitation ( ! p5tasulphide & ! r$uction ( ars5ic acid & ! subsequ5t precipitation ( ars5ic trisulphide4#ejf ,! int]e/+ obs]vation has also be5 made t1 9 ! pres5ce ( an unusually l>ge excess ( hydro*loric acid & ( a rapid /ream ( hydrog5 sulphide1 ! precipitation ( ! p5tasulphide 7equation 7#a77 is favor$ & accel]at$4#ejg ,= in/ance1 if #ajj c4c4 ( conc5trat$ hydro*loric acid 7sp4 gr4 #a4b7 are add$ to #ej c4c4 ( a #j4a mol> solution ( potassium ars5iate & a rapid /ream ( hydrog5 sulphide is pass$ ?r\gh ! mixture at ! ord9>y temp]ature1 a copi\s precipitate is =m$ )9 a m9ute 7exp474 ,! precipitate =m$ "u ^! conditions p#bdi is ! p5tasulphide4#ejh ,on ! o!r h&1 a mixture ( #e c4c4 ( hexanormal hydro*loric acid & #ej c4c4 ( #j4a mol> potassium ars5iate fails1 = a long "t1 to give a precipitate :5 treat$ 9 ! same way 7exp474 ,! accel]ation ( ! precipitation ( ! p5tasulphide by ! pres5ce ( a l>ge excess ( hydro*loric acid =ms a problem ( peculi> int]e/ & importance1 & no complete explanation ( x has yet be5 (f]$4#eji ,! foll[+ consid]ations lead to "o explanation1 t has be5 sugge/$4 ,ars5ic acid1 by virtue ( its close relations to antimonic1 /annic & ars5i\s acids1 may be assum$ to h extremely weak basic1 z well z pron\nc$ acid1 prop]ties4 ,= its ionization1 we w\ld h #c ,h ,as,o#dc ,h#c;,as,o#d 7 ,h#b,o7 ,z7,,oh7#e ,z#e #e ,,ho4 ,fur!r1 ! precipitation ( ,z#b,s#e may be assum$ to result1 ultimately1#eaj f ! action ( ! sulphide-ion ,s#b on ! positive ion ,z#e 7#b ,z#e #e ,s#b ,z#b,s#e 74 ,! favorable action ( ! hydro*loric acid might1 consequ5tly1 be ?\ght to result f ! fact1 t x facilitates ! ionization ( ars5ic acid z a base & ! =mation ( a salt#eaa ,as,cl#e4 ,x c\ld ?us greatly increase ! conc5tration ( ! ion ,z#e & facilitate its comb9ation ) ! sulphide-ion4 ,treatm5t ( a solution ( ars5ic acid ) a conc5trat$ acid1 yield+ a l>ge conc5tration ( hydrog5-ion1 w\ld c>ry ! s]ies ( actions1 repres5t$ 9 ! above ionization equation = ars5ic acid1 decid$ly t[>d ! "r--suppress+ ! ars5iate-ion ,as,o#dc & increas+ ! conc5tration ( ! ars5ic-ion ,z#e4 ,s9ce we _c apply ! equilibrium laws 7or ! pr9ciple ( ! solubility-product7 to solutions z conc5trat$ z ! "o "u discussion1 a quantitative !oretical treatm5t ( ! subject _c be giv54 ,! foll[+ may be sugge/$3 ,! action ( ! acid w\ld be favorable to ! precipitation ( ,z#b,s#e by suppress+ ! ars5iate-ion ,as,o#dc & ?us increas+ ! conc5tration ( ! hydroxide ,z7,,oh7#e1 available = ionization z a base & = ! production ( ! ion ,z#e4 ,b ! fur!r favorable effect ( ! hydro*loric acid1 9 conv]t+ ! hydroxide into a salt ,as,cl#e & increas+ !reby ! conc5tration ( ,z#e1 w\ld be v l>gely (fset by ! action ( ! acid 9 suppress+ ! p#bej sulphide-ion 7,s#b k _/ ,h#b2 see p4 #bja74 ,= sy/ems to :i* ! equilibrium laws c\ld be appli$1 ! conc5tration ( ,z#e 7except = ! suppression ( ! ion ,as,o#dc7 w\ld gr[1 approximately1 ) ! fif? p[]#eab ( ! conc5tration ( ! hydrog5-ion1 & ! conc5tration ( ! sulphide-ion w\ld decrease1 approximately1 proportionally to ! squ>e ( ! conc5tration ( ! hydrog5-ion4 ,fur!r1 ! precipitation ( ,z#b,s#e1 9 a sy/em to :i* ! pr9ciple ( ! solubility-product 7 applicable1 w\ld dep5d on ! relation ( ! product ,z#eb ,s#be to ! solubility-product con/ant2 x is evid5t t ! value = ,z#eb w\ld increase proportionally to ! t5? p[] ( ,h & ! value ( ,s#b decrease proportionally to ! t5? p[] ( ! same factor ,h4 ,! two effects w\ld consequ5tly (fset ea* o!r "u su* conditions4 ,h[ev]1 ! equilibrium laws _c legitimately be appli$ to su* conc5trat$ solutions & ! relation has be5 develop$ only to indicate oppos+ factors1 :i* mu/ be tak5 into acc\nt4 ,an exp]im5tal /udy ( ! problem w\ld be extremely int]e/+4#eac ,s9ce x involves ! "q ( ! m9ute basic ionization ( a mod]ately /rong acid 7,h#c;,as,o#d71 :i* may be op5 to measurem5t 7see ,*ap4 ,,xvi71 ! problem is "o ( p>ticul> int]e/ & importance4 ,! analytical precautions1 tak5 to insure ! precipitation1 by hydrog5 sulphide1 ( ars5ic sulphide1 :5 ars5ic is pres5t 9 qu9quival5t =m1 are bas$ on ! obs]vations describ$2 9 quantitative analysis1 = ! sake ( secur+ a precipitate ( uni=m composition1 ! aim is to precipitate ! pure p5tasulphide & a consid]able excess ( hydro*loric acid is us$4 ,9 qualitative analysis1 :]e ! composition ( ! precipitate is a matt] ( indiff]5ce & a l>ge excess ( acid w\ld s]i\sly int]f]e ) ! precipitation ( c]ta9 sulphides 7e4g4 ,cd,s1 see p4 #baa71 a small] excess ( acid is us$ & ! precipitation ( ars5ic sulphide is insur$ by prolong$ treatm5t ( a solution ) hydrog5 sulphide at a high temp]ature4 ,,footnotes3 #dib ,! weak basic prop]ties ( ! hydroxides ( ! alum9ium gr\p1 z comp>$ ) ^? ( ! z9c gr\p1 a *emical diff]5ce1 & ! result+ great in/ability ( ! c>bonates ( ! =m] gr\p1 are us$ 9 ! sep>ation ( ! alum9ium f ! z9c gr\p1 by b>ium c>bonate2 b ! physical elem5t ( extreme insolubility ( ! trival5t hydroxides ent]s also z an important factor 7see footnote #c1 p4 #aid74 #dic ,see p4 #bdg1 9 reg>d to ! behavior ( ars5ic acid 9 ?is respect4 #did ,see p4 #bdf1 footnote #c1 9 reg>d to ! action ( sodium sulphide on m]curic & bismu? sulphide4 #die ,vide ,nilson1 ,j4 prakt4 ,*41 #ad1 #aej 7#ahgf74 #dif ,su* a solution does n react alkal9e to ph5olph?alen4 #dig ,hydrog5 sulphide rapidly de/roys ! indicator & ! exp]im5t is be/ c>ri$ out by prep>+ #ej c4c4 ( a saturat$ aque\s solution ( hydrog5 sulphide1 conta9+ #a or #b c4c4 ( normal hydro*loric acid1 & by add+ a consid]able excess ( me?yl orange to ! solution imm$iately be=e ! addition ( potassium hydrosulphide solution1 :i* has be5 prep>$ z describ$ 9 ! text4 #dih ,see ! discussion on p4 #agg4 ,see also ! discussion by ,rems5 on acidic & basic halides1 ,am4 ,*em4 ,j41 #aa1 #cjj 7#ahhi7 ,/ud4 #dii ,9 bo? cases acid salts1 ,,khco#c & ,,khcs#c1 are also =m$4 #ejj ,mc,cay1 ,z4 anorg4 ,*em41 #bi1 #cf 7#aija74 #eja ,on p4 #bch ! analog\s equation = ! condition ( equilibrium ( ! anion ( an oxyg5 acid ) its compon5ts 0 develop$4 ,apply+ ! result to ! ion ,sn,o#cb ( /annic acid1 ,h#b,sn,o#c1 we h3 ,sn#d ,o#bc _/ ,sn,o#cb ,k4 ,x is evid5t1 f ! =m ( ! equation1 t = ! /rong] oxyg5 acids1 :i* are mo/ /able z acids & ionize z bases at mo/ 9 traces1 ! value ( ! con/ant mu/ be extremely small4 #ejb ,m]curic sulphide is some:at soluble 9 potassium & sodium sulphides1 =m+ ! salts ,me#b;,hg,s#b1 & ! complex ion ,hg,s#bb4 ,a lit] ( #j4a mol> ,na#b,s dissolves1 at #be1 #a4i grams 7#j4jjhb mole7 ( ,hg,s ,knox1 ,trans4 ,f>aday ,society1 #d1 #cf 7#aijh74 ,:ile ! oxide 7hydroxide7 %[s no p]ceptible t5d5cy t[>d acid ionization1 m]curic salts1 x w be recall$1 %[ 9 _m cases an abnormally small t5d5cy to =m ! m]curic-ion 7see p4 #aae71 & ! latt] also %[s a p>ticul>ly great t5d5cy t[>ds =m+ v /able complex ions ( all k9ds 7e4g4 ,hg,i#db1 9 ,k#b;,hg,i#d1 ,hg,cl#db 9 ,k#b;,hg,cl#d1 ,hg7,,cn7#db1 etc474 ,knox f\nd = ,hg#b ,s#bb _/ ,hg,s#bb k1 ! approximate value ( k to be #a _/ #ajec4 ,bismu? sulphide is also v sp>+ly soluble 9 sodium or potassium sulphide1 b n 9 ammonium sulphide4 ,solid salts1 ,k,bi,s#b & ,na,bi,s#b are kn[n ,knox1 ,j4 ,*em4 ,soc4 7,london71 #ie1 #agfj 7#aiji74 #ejc ,see ! table1 p4 #ajd4 #ejd ,see ! discussion ( ! reaction1 giv5 bel[4 #eje ,see ,*ap4 ,,xvi1 = ! int]pretation ( ! r$uction z an ionic reaction4 #ejf ,buns51 ,ann4 7,liebig71 #aib1 #cje 7#ahgh74 ,braun] & ,tomicek1 ,j4 ,*em4 ,soc4 7,london71 #ec1 #ade 7#ahhh74 ,u%] & ,trav]s1 ibid41 #hg1 #acgj 7#aije74 #ejg ,neh]1 ,z4 anal4 ,*em41 #cb1 #de 7#ahic74 #ejh ,neh]1 loc4 cit4 #eji ,! !ory ( ! relations favor+ ! precipitation express$ 9 equation 7#a7 z aga9/ ! r$uction express$ 9 equation 7#b71 =ms a second int]e/+ problem4 #eaj ,int]m$iate d]ivatives1 su* z ,h#c;,as,s,o#c 7p4 #bdf71 c\ld be ! result ( ! ionization ( ,z7,,oh7#e1 or ( ,as,cl#e1 9 /ages 7see p4 #ajf74 ,neh]1 loc4 cit41 ,mc,cay1 loc4 cit4 #eaa ,neh] 7loc4 cit47 sugge/$ t ! favorable action ( ! l>ge excess ( hydro*loric acid might well be due to ! =mation ( ,as,cl#e4 ,mc,cay1 ,j4 ,am4 ,*em4 ,soc41 #bd1 #ffa 7#aijb71 discusses ! ionization ( ars5ic acid z a base1 9 connection ) ! precipitation ( ,z#b,s#e4 #eab ,z7,,oh7#e is consid]$ to be an extremely weak base & ,as,cl#e to be an ionizable salt4 #eac ,to a c]ta9 ext5t1 ! effect ( ! acid may be to coagulate & precipitate ! colloidal sulphide4 ,possibly1 also1 ! conc5trat$ acid r5d]s inactive a consid]able portion ( ! wat] pres5t 7=m+ oxonium salts ,,oh#c;,cl1 etc41 see p4 #bch71 :i* t5ds1 by hydrolysis1 to rev]se ! =mation ( ! *loride ,z7,,oh7#e #e ,h,cl ,as,cl#e #e ,h#b,o4 ,possibly1 ! =mation ( ! p5tasulphide is n :olly an ionic reaction1 its precipitation be+ always a m or less sl[ process1 & !re may be int]m$iate products ^: =mation c\ld be accel]at$ by ! pres5ce ( acids 7see ,br$ig & ,walton1 ,z4 ,elektro*em41 #i1 #aad 7#aijc7 = ! /udy ( a simple inorganic action involv+ su* catalytic effects ( acids74 p#bea ,,*apt] ,,xiv ,,oxidation ,,& ,,r$uction ,,reactions4 ,i ,oxidation & r$uction reactions are frequ5tly met ) 9 analysis1 & we %all turn n[ to ! consid]ation ( su* reactions1 f ! po9t ( view ( ! mod]n !ory ( solution & ! laws ( equilibrium4 ,leav+ until lat] ! discussion ( ! mo/ important & mo/ common oxidiz+ ag5ts1 su* z oxyg51 nitric acid1 p]manganate1 etc41 we %all1 9 ord] to develop ! subject mo/ simply1 conf9e ourselves1 = ! mom5t1 to ! qualitative /udy ( "s oxidations & r$uctions met ) e>ly 9 ! /udy ( analytical reactions4 ,"o su* reaction is ! r$uction ( f]ric salts by hydrog5 sulphide1 & ! simultane\s oxidation ( ! latt] to sulphur 7exp474 ,! reaction may be express$ by ! equation #b ,fe,cl#c ,h#b,s #b ,fe,cl#b #b ,h,cl ,s 4 ,if ! action is consid]$ to be ! result ( ! int]action ( ! ioniz$ f]ric *loride & hydrog5 sulphide1 x w\ld be repres5t$ by ! equation #b ,fe#c #f ,cl #b ,h ,s#b #b ,fe#b #f ,cl #b ,h ,s 4 ,x is !n cle> t ! react+ compon5ts1 accord+ to su* a conception1 are ! f]ric & ! sulphide ions1 ^: electrical *>ges mutually dis*>ge ea* o!r4 ,consid]+ only ^? compon5ts ^: *>ges are *ang$1 we h #b ,fe#c ,s#b #b ,fe#b ,s 4 ,! r$uction ( a f]ric to a f]r\s salt w\ld !n be accompli%$ by ! dis*>ge ( "o ( ! ?ree positive *>ges on ! f]ric ions2 ! oxidation ( hydrog5 sulphide to sulphur w\ld be accompli%$ by ! complete dis*>ge ( ! sulphide ions4 ,f]ric salts are r$uc$1 mu* 9 ! same way1 by iodides 7exp471 iod9e be+ lib]at$3 #b ,fe#c #b ,i #b ,fe#b ,i#b4 ,r$uction !n appe>s to involve a loss ( positive *>ges by ions1 oxidation a loss ( negative *>ges4 p#beb ,conv]sely1 we frequ5tly h occasion to oxidize f]r\s salts to ! f]ric condition1 & among ! mo/ conv5i5t reag5ts = ! purpose are *lor9e & brom9e wat] 7exp474 ,= in/ance1 we h #b ,fe,cl#b ,cl#b #b ,fe,cl#c1 or1 consid]+ ! action f ! po9t ( view ( ! !ory ( ionization1#ead #b ,fe#b ,cl#b #b ,fe#c #b ,cl4 ,9 ?is case ! oxidation ( ! f]r\s to ! f]ric ion consi/s 9 ! assumption ( an additional positive *>ge2 r$uction ( *lor9e to ! *loride-ion consi/s 9 ! assumption ( negative *>ges by ! *lor9e atoms4 ,def9itions ( ,oxidation & ,r$uction 9 ,electric ,t]ms4--,! def9itions mu/ !n be amplifi$ & oxidation be consid]$ to involve ultimately ! assumption ( positive1 or ! loss ( negative1 electrical *>ges by ions or atoms1 r$uction to involve ultimately ! assumption ( negative1 or ! loss ( positive1 *>ges4 ,accord+ to ! electron !ory ( electricity a unit negative *>ge is an electron1 ! unit positive *>ge1 probably1 ! *>ge left on an atom :5 x has lo/ an electron2 &1 ?us1 oxidation may simply be def9$1 accord+ to ! electric !ory ( oxidation & r$uction1 z consi/+1 fundam5tally1 9 ! loss ( electrons by atoms or ions1 r$uction z consi/+ 9 a ga9 ( electrons4 ,= in/ance1 :5 hydrog5 sulphide r$uces a f]ric salt1 #b ,fe#c ,s#b #b ,fe#b ,s1 ! sulphide ions transf] _! electrons to ! f]ric ions4 ,oxidations & ,r$uctions by ,electric ,curr5ts4--,all ( ! oxidation & r$uction reactions :i* h be5 discuss$ may1 9 fact1 be effect$ by ! use ( an electric curr5t 9 ! place ( *emical ag5ts4 ,f]r\s salts1 = in/ance1 are oxidiz$1 at ! positive pole1 by ! curr5t to f]ric salts3#eae ,fe#b ,fe#c1 or ,fe#b ,fe#c4 ,f]ric salts are r$uc$1 at ! negative pole1 to f]r\s salts3 ,fe#c ,fe#b1 or ,fe#c ,fe#b4 p#bec ,,exp4--,a solution ( f]r\s *loride1 fre%ly prep>$ f iron wire1 or a fre%ly prep>$ solution ( f]r\s-ammonium sulphate1 is plac$ 9 a v small beak]2 a solution ( f]ric *loride1 acidulat$ ) hydro*loric acid to prev5t subsequ5t complete r$uction ( ! f]ric-ion to iron1 is br\ght into a simil> beak]4 ,a small am\nt 7#e c4c47 ( ea* solution is te/$1 ! =m] ) potassium ?iocyanate & ! latt] ) f]ricyanide solution1 to %[ ! abs5ce ( p]ceptible quantities ( f]ric & f]r\s ions 9 !m1 respectively4 ,plat9um electrodes1 consi/+ be/ ( cyl9d]s ( plat9um gauze1 are introduc$ into ! solutions1 ! solutions are connect$ by means ( a salt bridge 7a ,u-tube fill$ ) a solution ( sodium *loride & clos$ at bo? ends by plugs ( filt] pap]71 & a curr5t ( #j4b amp]e is pass$ ?r\gh ! sy/em1 ! positive curr5t ent]+ ! solution conta9+ ! f]r\s salt4 ,aft] ! curr5t has be5 all[$ to pass = a m9ute or two1 #e c4c4 is )drawn1 by a pipette1 f ! me%es ( ! positive electrode & te/$ ) ?iocyanate1 & #e c4c41 )drawn 9 ! same way f ! negative electrode1 is te/$ ) potassium f]ricyanide4 ,production ( ,electric ,curr5ts by ,means ( ,oxidation & ,r$uction ,reactions4--,n only may all ! oxidations & r$uctions :i* we h discuss$ be accompli%$ ) ! aid ( ! electric curr5t1 b vice v]sa1 an electric curr5t may readily be produc$ by a prop] arrangem5t ( ! compon5ts ( any "o ( ^! reactions4 ,c>e ne$ only be tak5 to h ! simultane\s loss & ga9 ( electrons1 *>act]i/ic ( all oxidation & r$uction reactions1 occur 9 sep>ate localities1 :i* mu/ be connect$1 h[ev]1 9 su* a way z to make ! transf] ( electrons1 a fl[ ( electricity1 possible4 ,,exp4 ,= in/ance1 "s f]ric *loride & sodium *loride solution may be put into a small beak]1 "s sodium *loride solution into a second beak] ( ! same size1 & ! two solutions connect$1 fir/ by means ( a salt-bridge1 & !n by means ( two plat9um electrodes dipp+ into ! solutions & connect$ ) ! t]m9als ( a s5sitive voltmet]4#eaf ,if p#bed all ( ! connections are made1 ! introduction ( ! salt-bridge be+ left to ! la/1 a mom5t>y slight motion ( ! ne$le is obs]v$1 :5 ! bridge is introduc$4 ,! ne$le !n falls back to ! z]o po9t 7see p4 #bgf74 ,if n[ "s hydrog5 sulphide wat] is p\r$ into ! beak] conta9+ sodium *loride1 a decid$1 & cont9u+1 deflection ( ! ne$le ( ! voltmet] is imm$iately obs]v$1 %[+ ! passage ( an electric curr5t1 & x is 9 ! direction anticipat$ by ! consid]ation ( ! reaction equation3 #b ,fe#c ,s#b #b ,fe#b ,s 4 ,! positive curr5t passes into ! voltmet] f ! f]ric *loride solution1 :]e f]ric ions are giv+ up _! *>ges2 ! negative curr5t ent]s ! voltmet] f ! solution conta9+ ! hydrog5 sulphide1 :]e sulphide ions are be+ dis*>g$4 ,! salt-bridge is necess>y to complete ! electrical circuit & prev5t any local accumulation ( positive or negative electricity 7pol>ization74 ,= in/ance1 z ! f]ric ions are dis*>g$1 an excess ( *loride ions w\ld rema9 9 ! beak]1 r5d]+ ! solution negative & prev5t+ ! fl[ ( electricity f ! electrode1 if negative ions did n move (f1 ?r\gh ! salt-bridge1 into ! beak] conta9+ hydrog5 sulphide &1 simultane\sly1 positive ions migrate into ! beak] conta9+ ! f]ric salt4 ,simil>ly1 ! accumulation ( positive electricity 9 ! hydrog5 sulphide solution1 on acc\nt ( ! hydrog5 ions left free by ! dis*>ge ( sulphide ions1 is prev5t$ by ! fl[ ( positive ions 7sodium & hydrog57 ?r\gh ! ,u-tube into ! beak] conta9+ ! f]ric *loride & ! fl[ ( negative 7*loride7 ions into ! hydrog5 sulphide solution4 ,?us a curr5t ( electricity passes ?r\gh ! :ole circuit4 ,x is ?us possible to r$uce f]ric *loride 9 "o vessel by hydrog5 sulphide p\r$ into ano!r vessel1#eag & an electric curr5t may be obta9$ f ! simultane\s dis*>ge ( ! sulphide & f]ric ions 9 ! action4 ,effects ( ,ion ,conc5trations on ! ,curr5t4--,hydrog5 sulphide1 x w be recall$1 is an extremely weak acid 7p4 #aii71 only a v small proportion is ioniz$ &1 consequ5tly1 ! conc5tration ( ! dis*>g+ 7r$uc+7 sulphide-ion mu/ be m9ute 9 ?is solution4 ,its salts1 h[ev]1 are highly ioniz$1 & by ! addition ( an alkali to ! solution conta9+ ! hydrog5 sulphide1 ! conc5tration ( ! dis*>g+ ion w\ld be v greatly increas$ & ! curr5t %\ld !re=e be int5sifi$ mo/ decid$ly--provid$ ! hydrog5 sulphide really r$uces by means ( its negative ion & n by ! action ( ! nonioniz$ acid4 ,z a matt] ( fact1 ! anticipat$ decid$ increase 9 ! int5sity ( ! curr5t is obs]v$1 :5 alkali is add$ to ! mixture conta9+ ! hydrog5 sulphide 7exp474 ,simil>ly1 p#bee we h assum$ t ! oxidiz+ ag5t is ! highly *>g$ f]ric-ion1 n ! nonioniz$ f]ric salt4 ,n[ iron =ms r /able complex ions#eah ) ! fluoride-ion1 = in/ance1 ,fe,f#fc1 :i* yield f]ric ions v mu* less readily ?an d f]ric salts4 ,h5ce ! addition ( a fluoride--potassium or ammonium fluoride--%\ld1 accord+ to ?is view1 r$uce ! oxidiz+ p[] ( ! iron solution by suppress+ ! f]ric-ion & conv]t+ x into ! complex ,fe,f#fc4 ,9 fact1 ! addition ( potassium fluoride imm$iately r$uces ! int5sity ( ! curr5t 7exp471 &1 simultane\sly1 ! deep yell[-br[n color ( ! f]ric salt solution gives way to ! v pale yell[ t9t ( ! complex ion & its salt4#eai ,fur!r ,illu/rations4--,if f]r\s sulphate solution is put into "o beak] & sodium *loride solution into ano!r1 connections be+ made simil> to ^? us$ 9 ! previ\s exp]im5t1 !n a vigor\s curr5t is in/antly produc$ 7exp471 :5 "s brom9e or *lor9e wat] is add$ to ! sodium *loride solution1 ! positive curr5t fl[+ into ! voltmet] f ! beak] conta9+ ! brom9e 7*lor9e72 ! brom9e atoms 7*lor9e atoms7 comb9e ) electrons lo/ by ! f]r\s ions & are r$uc$ to bromide ions 7*loride ions7 7see p4 #beb74 ,x w\ld appe> possible1 9 fact1 to obta9 an electrical curr5t f any oxidation-r$uction reaction1 if ! oxidiz+ & r$uc+ ag5ts c be1 exp]im5tally1 prop]ly arrang$ = ?is purpose4 ,summ>y4--,we f9d ?us t !re is a mo/ intimate connection betwe5 oxidation & r$uction ph5om5a & electrical *>ges on atoms or ions4 ,9 ! fir/ place1 an electrical curr5t may be us$ z an oxidiz+ & r$uc+ ag5t2 inde$1 a curr5t _c be pass$ ?r\gh any solution )\t simultane\s oxidation & r$uction at ! positive & negative poles1 respectively4 ,&1 conv]sely1 an electric curr5t may1 9 turn1 be produc$ by a prop] comb9ation ( ! reag5ts 9 oxidation & r$uction reactions4 ,ne$ ( ! ,/udy ( ! ,quantitative ,relations4--,! int]pretation ( su* actions f ! po9t ( view ( ! !ory p#bef ( ionization (f]s1 !n1 no p>ticul> difficulties4 ,b1 z f> z we h develop$ ! !ory1 t is1 ess5tially f its qualitative side1 difficulty w\ld be enc\nt]$ 9 und]/&+ :y c]ta9 o!r reactions1 involv+ a simil> simultane\s dis*>ge ( positive & negative electricity by ions1 :i* might be expect$ to take place1 d n seem to take place4 ,?us1 solutions ( f]ric sulphate d n appe> to be r$uc$ appreciably by ! hydroxide & oxide ions ( ! wat] pres5t4 ,al?\gh ! possibility ( su* a r$uction exi/s ?r\gh ! simultane\s dis*>ge ( ! positive electricity ( ! f]ric ions & ! negative *>ge on ! oxide ions 7or hydroxide ions7 ( wat] 7#d ,fe#c ,o#b #d ,fe#b ,o#b or #d ,fe#c #d ,,ho #d ,fe#b ,o#b #b ,h#b,o71 comp>able ) ! r$uction ( f]ric ions by sulphide ions1 su* a r$uction does n take place appreciably4#ebj ,&1 simil>ly1 :]eas ! iodide-ion1 z we h se51 r$uces ! f]ric-ion v readily1 ! analog\s *loride-ion does n appe> to d s4 ,sodium *loride may be add$ to f]ric sulphate solution & potassium f]ricyanide fails to %[ t any f]r\s salt is produc$ 7exp474 ,! m]e possibility ( a transf] ( *>ges1 or electrons1 is !re=e app>5tly#eba n suffici5t to induce an oxidation & r$uction reaction--mu* 9 ! same way z1 = in/ance1 ! m]e pres5ce1 simultane\sly1 ( ! b>ium-ion & ! c>bonate-ion1 9 itself1 does n necess>ily lead to ! precipitation ( b>ium c>bonate 7p4 #ij71 al?\gh ! latt] is difficultly soluble4 ,9 ord] to und]/& ! problem ( precipitation or nonprecipitation ( salts1 x 0 f\nd necess>y to exam9e ! "q f its quantitative side 7p4 #ia71 &1 simil>ly1 ! solution ( ! difficulty conc]n+ ! occurr5ce or nonoccurr5ce ( oxidation & r$uction reactions1 :]e ! possibility ( a transf] ( electrons is giv51 w be f\nd 9 a /udy ( ! problem f its quantitative side4 ,oxidation & ,r$uction ,reactions z ,rev]sible ,reactions4--,9 ord] to r$uce ! developm5t ( ! quantitative p#beg relations to ! simple/ possible t]ms1 we may turn to /ill simpl] oxidation & r$uction reactions ?an ^? /udi$ ?us f>4 ,if a rod ( z9c is plac$ 9 a solution ( copp] sulphate1 copp] is deposit$ & z9c sulphate is =m$4 ,if we consid] ! action to be an ionic "o1 we h3 ,cu#b ,,s#db ,zn ,zn#b ,,s#db ,cu 1 or1 s9ce ! sulphate-ion is n directly conc]n$ 9 ! action1 we h m simply3 ,cu#b ,zn ,cu ,zn#b4 ,cupric-ion has be5 r$uc$1 !re=e1 to metallic copp]1 ! metallic z9c oxidiz$ to z9c-ion1 ea* z9c atom transf]r+ two electrons to a cupric ion4 ,clos] analysis ( ! action %[s t ?is int]pretation ( ! action1 f ! electrical po9t ( view1 is n at all 9 conflict ) ! old] def9itions & conceptions ( oxidation & r$uction3 copp] is depriv$ ( ! oxyg5 ) :i* x is comb9$ 9 nonioniz$ copp] sulphate1 ,o ,cu ,,s#b1 & by evaporation ( ! solution1 ,o ,o z9c sulphate1 ,zn ,,s#b1 ,o conta9+ ! z9c comb9$ ) oxyg51 is obta9$4 ,we %all pres5tly f9d1 h[ev]1 t x is j 9 ! quantitative =mulation ( ! relations1 t ! int]pretation ( ! action f ! po9t ( view ( ! !ory ( ionization has prov$ its sup]iority ov] ! old] view4 ,if a /rip ( copp] is plac$ 9 a solution ( m]curic nitrate1 copp]1 9 turn1 is dissolv$1 be+ oxidiz$ to ! =m ( cupric-ion1 & m]cury is deposit$3 ,cu ,hg#b ,cu#b ,hg 4 ,we f9d1 !n1 t cupric-ion has a t5d5cy to give up its *>ges1 to be r$uc$ to ! metallic condition2 metallic copp]1 9 turn1 has a t5d5cy to rev]t to ! ionic condition1 to be oxidiz$ & to =m cupric-ion4 ,we may consid] ! two oppos$ t5d5cies1 %[n 9 ^! relations1 z repres5t+ a rev]sible reaction3 ,cu ,cu#b4 ,,exp4 ,if an electric curr5t is pass$ ?r\gh a copp] sulphate solution1 copp] is deposit$ on ! negative 7plat9um7 electrode2 if ! curr5t is rev]s$1 ! copp] vani%es q z rapidly at :at is n[ ! positive pole4 p#beh ,condition ( ,equilibrium4--,= su* a rev]sible reaction we might expect1 if we may apply ! law ( equilibrium to x1 t ! ratio ( ! conc5trations ( copp] & ( ! cupric-ion w\ld be a con/ant = ! condition ( equilibrium at a giv5 temp]ature4#ebb ,we w\ld !n h3 ,cu#b _/ ,cu k4 ,s9ce ! conc5tration ,cu ( a pure1 d5se#ebc piece ( copp] may be consid]$ a con/ant at a giv5 temp]ature1 x w\ld foll[1 t ! fir/ t]m 9 our relation w\ld also h a con/ant def9ite value = ! condition ( equilibrium betwe5 ! metal & its ion4 ,consequ5tly1 = ! condition ( equilibrium we w\ld h3 ,cu#b ,k,cu#b4 ,metallic copp] w\ld !n be 9 equilibrium1 at a giv5 temp]ature1 ) solutions conta9+ cupric-ion only if ! latt] has a p]fectly def9ite1 con/ant conc5tration4 ,n]n/#ebd discov]$ ?is & simil> relations1 z a result ( a m rigor\s analysis ( ! en]gy *anges involv$ 9 ! ionization & precipitation ( metals1 & prov$ ! validity ( ! relations4 ,! value ( ! con/ant1#ebe :i*1 accord+ to ,n]n/'s p#bei sugge/ion is call$ ! electrolytic solution-t5sion con/ant1 is #h;,e#bb = copp]#ebf2 t is1 copp] is directly 9 equilibrium ) a solution conta9+ cupric-ion only if ! conc5tration ( ! latt] is #h;,e#bb gram-ion p] lit]4 ,we see1 !n1 t copp] w\ld be directly 9 equilibrium ) solutions ( cupric salts only if !y conta9 ?is exce$+ly m9ute conc5tration ( cupric ions4 ,:5 su* is ! case1 ! ionization ( ! metal & ! =mation ( ! metal1 by ! deposit ( dis*>g+ ions1 may be consid]$ to proce$ ) ! same velocity 7p4 #id74 ,b1 if ! metal is dipp$ into a solution ( great] conc5tration ( cupric ions ?an t repres5t$ by ! con/ant1 say into a solution ( #j4a mol> copp] sulphate1 ! velocity ( deposition ( ! metal w\ld be proportionally increas$ 7p4 #ib71 :ile ! velocity ( ionization & solution ( ! metal w\ld rema9 un*ang$4 ,we w\ld consequ5tly h ! ions dis*>g+ & =m+ metal m rapidly ?an !y are =m$4 ,a condition ( *ange1 n ( equilibrium1 exi/s4 ,if we p#bfj consid] ! *anges t mu/ occur1 we see t ! ions1 dis*>g+ on ! metal1 w\ld *>ge x ) positive electricity1 & ! positive *>ge w\ld1 9 turn1 repel f ! metal ! positive cupric ions rema9+ 9 ! solution4 ,equilibrium w\ld be expect$ to result :5 ! *>ge on ! plate becomes heavy en\gh to repel f ! film1 imm$iately surr\nd+ x1 all ! cupric ions except+ ^? repres5t+ a conc5tration ( #h;,e#bb1 z requir$ by ! value ( ! equilibrium con/ant4 ,! positive *>ge on ! plate w\ld attract & hold negative sulphate ions1 fre$ by ! dis*>ge ( cupric ions1 9 a k9d ( d\ble lay]1 ! surface ( ! metal hold+ positive *>ges & ! film ( liquid 9 contact ) x hold+ an excess ( negative ions4 ,an electric pot5tial w\ld ?us be e/abli%$ betwe5 ! positive metal & ! negative solution1 ba?+ x4#ebg ,x is evid5t t ! m conc5trat$ ! solution ( cupric ions1 ! heavi] ! *>ge mu/ be t w be requir$ to repel ! cupric ions suffici5tly to e/abli% equilibrium4#ebh ,if copp] is plac$ 9 a solution 9 :i* ! conc5tration ( ! cupric ions is small] ?an ! con/ant #h;,e#bb1 ! velocity ( ionization w be great] ?an ! velocity ( ! deposition ( ! metal4 ,! ions =m$1 hav+ assum$ positive *>ges1 w leave a negative *>ge on ! metal1 &1 z a result ( ! electrical attraction1 a d\ble lay]1 surr\nd+ ! metal1 w aga9 be =m$1 ! positive ions cl++ to ! negative metal4 ,equilibrium w be rea*$ :5 ! conc5tration ( ! cupric ions orig9ally pres5t1 increas$ by ! new ions =m$ 9 ?is d\ble lay]1 w h rea*$1 9 ! film ba?+ ! plate1 ! conc5tration dem&$ by ! equilibrium con/ant4 ,an electrical pot5tial w be e/abli%$ z be=e1 ! metal be+ negative1 ! solution1 9 ?is case1 positive4 ,by develop+ ! quantitative relations betwe5 osmotic =ces & ! electrical pot5tial1 ,n]n/#c 0 able to %[ t1 at room temp]ature#ebi 7#ag-ah71 ! foll[+ log>i?mic relation p#bfa holds = ! pot5tial diff]5ce betwe5 a metal#ecj & a solution ( its ion1 :i* ba!s x3 ,me1 ,me-salt 7#j4jege _/ v7 log7,c _/ ,k74 ,9 ?is equation ,me1 ,me-salt is ! electrical pot5tial1 9 volts1 exi/+ betwe5 ! metal ,me & ! solution ( its salt1 ,me-salt2 v is ! numb] ( electrical *>ges transf]r$ f ! metal to its ion1 & vice v]sa1 9 ! action ,me ,meion2 9 ! pres5t case1 x is id5tical ) ! val5ce ( ! metal ion1 :i* ! metal =ms4 ,c is ! conc5tration ( ?is ion 9 any giv5 case1 & ,k is ! conc5tration repres5t$ by ! solution-t5sion con/ant1 i4e4 by ! equilibrium con/ant4 ,! log>i?m is ! common "o4 ,9 place ( ! conc5trations1 ,k & ,c1 ! correspond+ osmotic pressures ( ! metal ion 7,p & p1 z us$ by ,n]n/7 may be us$ 9 ! equation1 & = solutions 9 :i* osmotic pressure & conc5tration are n /rictly proportional1 ! osmotic pressure %\ld be us$ by pref]5ce 7see footnote #d1 p4 #beh74 ,! sign#eca giv5 to p#bfb ,me1 ,me-salt1 9 any giv5 case1 %[s ! sign ( ! electric *>ge on ! fir/ compon5t nam$ 9 ! subscript1 :i* is ! metal1 9 ! pres5t in/ance4 ,= ! relation betwe5 copp] & cupric-ion we w\ld h3 ,cu1 ,cu-salt 7#j4jege_/b7 log7,c _/ ,k74 ,:5 ! conc5tration ( cupric-ion is equal to ! con/ant1 ,c ,k1 ! log>i?m has ! value #j & ! pot5tial diff]5ce is #j4 ,:5 ! conc5tration ( cupric-ion is small] ?an ! con/ant1 ,c ,k1 ! pot5tial ,cu1 ,cu-salt is negative1 i4e4 ! metal receives a negative *>ge4 ,?is negative *>ge is ! great]1 ! small] ,c is4 ,:5 ,c ,k1 ,cu1 ,cu-salt is positive1 ! copp] plate receives a positive *>ge1 & ?is positive *>ge is ! great]1 ! l>g] ! value ( ,c is4 ,applications4--,x %\ld be cle>1 f ^! consid]ations1 t an electric curr5t w result1 if copp] plates are introduc$ into solutions conta9+ diff]5t conc5trations ( cupric-ion & ! solutions & electrodes are connect$ 9 su* a way z to all[ ! fl[ ( a curr5t4 ,if we call ,cu ! copp] plate dipp+ into a solution conta9+ cupric-ion at a conc5tration ,c1 & ,cu ! plate 9 a solution conta9+ ,cu#b ,c1 we h#ecb3 p#bfc ,cu1 ,cu ,cu1 ,cu,x ,cu1 ,cu,x 7#j4jege _/ #b7 log7,c _/ ,k7 log7,c _/ ,k7 &#ecc ,cu1 ,cu 7#j4jege _/ #b7 log7,c _/ ,c74 ,x is also cle>1 f ?is equation1 t ! great] ! diff]5ce 9 conc5tration ( ! cupric-ion 9 ! two solutions1 ! great] %\ld be ! pot5tial diff]5ce produc$4 ,! foll[+ s]ies ( exp]im5ts illu/rates ^! relations & confirms ! conclusions rea*$4 p#bfd ,if two electrodes ( pure copp] are introduc$ into solutions ( cupric sulphate ( equal conc5tration1#ecd no curr5t is produc$1 :5 ! solutions are connect$ by a salt bridge & ! electrodes ) a voltmet] 7exp42 ! *emomet] describ$ on p4 #bec is us$74 ,if "o ( ! beak]s is p>tially empti$1 only a few drops ( ! solution be+ left 9 x1 & is !n fill$ ) a solution ( sodium sulphate1 we notice t ! voltmet] imm$iately indicates ! e/abli%+ ( a pot5tial diff]5ce--a curr5t is produc$4 ,f ! exp]im5tal arrangem5t & f ! mann] ( ! deflection ( ! ne$le ( ! *emomet]1 we note1 too1 t ! plate dipp+ into ! m conc5trat$ solution ( ! cupric-ion is ! positive pole1 & h5ce ! cupric ions are dis*>g$ on x2 ?is solution is !re=e gr[+ less conc5trat$ 9 reg>d to cupric-ion4 ,9 ! o!r vessel1 copp] is dissolv+ & ! conc5tration ( cupric-ion is increas+4 ,bo? *anges t5d t[>d equaliz+ ! conc5trations 9 ! two solutions & ?us t[>d e/abli%+ equilibrium4 ,! diffusion ( ions1 f & to ! plates1 is a v sl[ process 7p4 #h71 & s9ce ! pot5tial produc$ dep5ds on ! mom5t>y conc5trations ( ! liquid films imm$iately next to ! plates1 ! pot5tial diff]5ce1 fir/ obs]v$1 is se5 to disappe> rapidly4 ,m decid$ & la/+ pot5tial diff]5ces are obta9$ by introduc+ reag5ts1 :i* keep ! conc5tration ( ! cupric-ion1 automatically1 at v l[ values 9 ! "o solution1 & :i* ?us make u less dep5d5t on ! sl[ diffusion ( ! ions ar\nd ! plates4 ,we may add1 = in/ance1 sodium hydroxide to a solution ( copp] sulphate to precipitate cupric hydroxide2 cupric hydroxide be+ a difficultly soluble comp\nd1 its saturat$ solution conta9s only a v small conc5tration ( p#bfe cupric-ion4 ,if we connect1 aga91 copp] plates 9 two equally conc5trat$ solutions ( copp] sulphate1 & add a little m ?an ! equival5t am\nt ( sodium hydroxide to ! solution hold+ ! plate connect$ ) ! negative po/ ( ! voltmet]1 cupric hydroxide is !reby precipitat$1 & we note t a decid$ diff]5ce ( pot5tial is e/abli%$ & ma9ta9$ 7exp474 ,an excess ( a conc5trat$ solution ( sodium hydroxide %\ld1 accord+ to ! pr9ciple ( ! solubility-product1 r$uce ! conc5tration ( cupric-ion /ill m1 & ! pot5tial is1 9 fact1 !reby increas$ 7exp474 ,cupric sulphide is mu* less soluble ?an cupric hydroxide1 & if we add sodium sulphide 7a little m ?an "o equival5t7 to ! mixture conta9+ ! hydroxide1 we f9d t ! hydroxide is conv]t$ into ! less soluble1 black sulphide1 leav+ a /ill small] conc5tration ( cupric-ion 9 ?is solution1 & ! pot5tial is aga9 increas$ 7exp474 ,we f\nd t ! complex ions ( copp] ) ! cyanide-ion are s extremely /able z to all[ ( ! exi/5ce ( a conc5tration ( cupric-ion s m9ute1 t copp] sulphide _c be precipitat$ f cyanide solutions 7p4 #bbh74 ,if suffici5t potassium cyanide is add$ to ! mixture conta9+ ! susp5sion ( cupric sulphide1 ! sulphide dissolves readily1#ece & ! l>ge/ pot5tial diff]5ce1 yet not$1 is produc$4#ecf ,we f9d ?us t ! behavior ( ! metal1 9 contact ) ^! diff]5t solutions1 agrees ) ! dem&s ( ! !ory4 ,! ,equilibrium ,relations betwe5 ,two ,metals & ,_! ,ions4--,! t5d5cy ( a metal to ionize & ( its ion to be r$uc$ has be5 aptly lik5$ to ! t5d5cy ( a liquid to =m its vapor & ( ! vapor to cond5se to its liquid 7! "n solution t5sion expresses ! analogy to vapor t5sion74 ,z diff]5t liquids h va/ly diff]5t t5d5cies to vaporize at a giv5 temp]ature1 s diff]5t metals1 diff]5t elem5ts1 h va/ly diff]5t t5d5cies to ionize4 ,we %all consid]1 briefly1 ?is t5d5cy also 9 ! case ( z9c4 ,9 aque\s solutions1 ! conc5tration ( z9c-ion ) :i* ! metal w\ld be 9 equilibrium1 z f\nd by calculation f ! pot5tial diff]5ce betwe5 z9c & z9c sulphate solutions p#bff ( realizable conc5trations ( z9c-ion1 is #ajag1 a value#ecg enorm\sly l>g] ?an #ajba1 ! value ( ! correspond+ con/ant = copp]4 ,a z9c rod1 9 contact ) a solution ( a z9c salt1 l z9c sulphate1 w acquire a negative *>ge1 z ! metal mu/ ionize mu* m rapidly ?an ! ion w be dis*>g$1 s9ce ev5 a saturat$ solution w\ld conta9 only a relatively small conc5tration ( ! ion4 ,copp]1 z we h se51 plac$ 9 a copp] sulphate solution ( mod]ate conc5tration1 is *>g$ ) positive electricity1 ! conc5tration ( cupric-ion be+ v mu* l>g] ?an t requir$ = ! condition ( equilibrium betwe5 ! metal & its ion4 ,:5 z9c1 imm]s$ 9 a z9c sulphate solution1 & copp]1 imm]s$ 9 a copp] sulphate solution1 are connect$ ?r\gh a metal circuit1 e4g4 t ( a voltmet]1 & ! solutions are connect$ by a salt-bridge 7exp471 a curr5t is e/abli%$1 ! positive curr5t fl[+ f ! copp] ?r\gh ! metal circuit to ! z9c1 metallic copp] be+ deposit$ & z9c go+ into solution4 ,! comb9ation repres5ts ! well-kn[n ,daniell cell4 ,we note t 9 ea* solution ! *ange 9 conc5tration ( ! ion is t[>ds ! solution-t5sion con/ant1 t[>ds a condition ( equilibrium4 ,we may inquire1 a little m closely1 :at w\ld be ! condition = equilibrium = su* a sy/em4 ,if we imag9e a copp] plate dipp+ into a solution conta9+ a conc5tration ( #ajba ( cupric-ion 7! solution-t5sion con/ant71 ! metal w be directly 9 equilibrium ) ! solution & w n acquire any electrical *>ge4 ,if we imag9e a z9c rod imm]s$1 9 ! same way1 9 a solution conta9+ a conc5tration ( z9c-ion ( #ajag 7?is is n practically feasible71 ! metal & its ion w\ld also be 9 equilibrium ) ea* o!r & ! metal w\ld n assume any *>ge4 ,x is evid5t t1 if ! z9c & copp] & ! solutions ( _! salts 7 connect$1 no curr5t w\ld be e/abli%$1 p#bfg z9c w\ld n be oxidiz$ to z9c-ion1 & cupric-ion w\ld n be r$uc$4 ,9 ?is condition ( equilibrium1 !n1 ! ratio ( ! conc5trations ( ! respective ions 9 ! solutions ba?+ ! metals w\ld be1 also1 ! ratio ( ! solution-t5sion con/ants4 ,?is is a g5]al relation = ^! two metals--! individual conc5trations ( ! ions ne$ n h ! value ( ! solution-t5sion con/ants1 b equilibrium w be e/abli%$ :5ev] ! ratio ( ! conc5trations ( ! cupric-ion & ! z9c-ion has ! same value z ! ratio ( ! solution-t5sion con/ants4#ech ,! condition = equilibrium1 9 ma!matical =m1 is !n ,zn#b _/ ,cu#b ,k,zn _/ ,k,cu ,keq42 & ,k,zn _/ ,k,cu #ajag _/ #a;,e#ba #ajch ,keq4 ,! ne>] ! ratio is to ! equilibrium con/ant1 ! small] ! pot5tial w be1 until1 :5 ! con/ant is rea*$1 x becomes #j4 ,we _c increase ! conc5tration ( z9c-ion indef9itely 9 ord] to rea* ! condition ( equilibrium1 b we may r$uce ! conc5tration ( cupric-ion practically at w1 z we h se5 7p4 #bfe71 & we may ?us approa* ! con/ant4 ,9 fact1 if we add to ! copp] sulphate solution ( ! copp]-z9c elem5t1 describ$ above1 a solution ( sodium hydroxide1 & ?us leave1 9 ! solution1 only ! small conc5tration ( cupric-ion belong+ to ! difficultly soluble cupric hydroxide1 ! pot5tial ( ! copp]-z9c elem5t is decid$ly r$uc$ 7exp474 ,if sodium sulphide is add$ to ! cupric hydroxide1 to conv]t ! hydroxide into ! less soluble sulphide1 :i* yields a small] conc5tration ( cupric-ion1 ! pot5tial is aga9 r$uc$ mo/ decid$ly 7exp474 ,x has n[ s small a value t we may readily anticipate t1 if ! cupric-ion is suppress$ s ?or\ghly1 by ! addition ( potassium cyanide1 t ev5 ! sulphide _c p]si/1 ! value ( ! ratio ,zn#b 3 ,cu#b may gr[ ev5 l>g] ?an ! p#bfh equilibrium con/ant #ajch1 & we w\ld h a sy/em 9 :i* *emical *ange 9 ! opposite direction mu/ result f ! t5d5cy to e/abli% equilibrium4 ,9 fact1 if potassium cyanide is add$ to ! mixture surr\nd+ ! copp] plate1 9 suffici5t quantity to dissolve ! sulphide1 we f9d t a curr5t is e/abli%$ 9 ! opposite direction#eci--z9c is n[ precipitat$ at ! exp5se ( ! solution ( metallic copp]2 t means1 t ! z9c-ion is be+ r$uc$ by metallic copp]1 :i* 9 turn is oxidiz$ to cupric-ion 7exp474 ,we may apply ! conclusions1 rea*$1 to ! action ( metallic z9c :5 x is introduc$ into ! solution ( a cupric salt4 ,! oxidation ( z9c to ! z9c-ion & ! r$uction ( ! cupric-ion to copp] mu/ be rev]sible reactions1 ,zn ,cu#b ,zn#b ,cu 1 :i* w come to a condition ( equilibrium1 accord+ to ! laws ( equilibrium1 :5 ,zn#b 3 ,cu#b ,k #ajch4 ,! value ( ?is ratio %[s t ! cupric-ion w be practically completely r$uc$1 & precipitat$ z copp]1 by a suffici5t quantity ( z9c1 ! trace ( cupric-ion1 requir$ to ma9ta9 ! equilibrium ratio1 be+ too m9ute to be detect$4 ,by ! /udy ( ?is oxidation & r$uction reaction ) ! aid ( pot5tial diff]5ces1 z j describ$1 ! validity ( ! relation is subject to demon/ration1 & ! value ( ! equilibrium con/ant is br\ght into def9ite relation to ! solution-t5sion con/ants ( ! metals4 ,ea* elem5t has its own *>act]i/ic solution-t5sion con/ant 7see ! table at ! end ( ,*apt] ,,xv71 & ! relation j e/abli%$ = ! r$uction ( cupric-ion1 at ! exp5se ( ! oxidation ( metallic z9c1 may be appli$ to any pair ( metals & _! ions4#edj ,g5]al ,pr9ciples ,conc]n+ ,equilibrium 9 ,rev]sible ,oxidation & ,r$uction ,reactions4--,we may n[ ext5d ! conclusions1 rea*$ 9 ! /udy ( ^! p>ticul>ly simple oxidations & r$uctions1 to oxidation & r$uction reactions 9 g5]al4 ,we mu/ expect t1 :5 su* an action is rev]sible & subject to ! laws ( equilibrium1 its c\rse w1 z 9 all p#bfi previ\s applications ( ! equilibrium laws1 dep5d1 at a giv5 temp]ature1 9 ! fir/ place1 on ! values ( con/ants4 ,! 7solution-t5sion7 con/ants1 involv$ 9 ?is class ( actions1 measure :at we may call ! aff9ity ( atoms & ions = electric *>ges1 or electrons4 ,9 ! second place1 ! c\rse ( ! action w dep5d1 9 ea* case1 on ! conc5trations ( ! ions1 conc5trations :i* are1 to a consid]able ext5t1 v>iable at w1 z we g f case to case4 ,9 ! ?ird place1 all su* rev]sible reactions w come ultimately to a condition ( equilibrium1 9 :i* nei!r action is absolutely complet$1 & ! c\rse ( ! action1 9 any giv5 sy/em n 9 equilibrium1 w always proce$ t[>d ?is condition ( equilibrium4 ,! oxidation & r$uction reactions1 su* z ,zn ,cu#b ,cu ,zn#b1 to :i* we h h]et(ore limit$ ! discussion ( ! quantitative relations1 are p>ticul>ly simple actions1 involv+ only two v>iables 79 ?is case ,cu#b & ,zn#b74 ,b ! k ( ! g5]al pr9ciples ( ! quantitative relations w n[ enable u to answ] que/ions1 9 connection ) m complicat$ cases1 :i* ! qualitative relations alone did n put u into ! position ( answ]+ 7see p4 #bef74 ,applications2 ,r$uction ( ,f]ric ,salts & ,oxidation ( ,f]r\s ,salts4--,x w n be difficult to arrive n[ at def9ite conceptions z to :y c]ta9 reactions ( oxidation & r$uction d n seem to take place1 al?\gh !y are1 qualitatively1 entirely analog\s to reactions :i* take place readily4 ,! /udy ( "o ( ! que/ions previ\sly rais$ 7see p4 #bef71 namely z to :y f]ric ions app>5tly are n r$ucible by *loride ions1 :ile !y are easily r$uc$ by iodide ions1 w be suffici5t to illu/rate ! application ( ! pr9ciples4 ,9 consid]+ ! "q ( ! possible r$uction ( f]ric to f]r\s ions1 at ! exp5se ( ! oxidation ( *loride ions to *lor9e1 we mu/ be> 9 m9d ! fact t ! r$uction ( ! f]ric ions is a rev]sible process1 ,fe#c ,fe#b1 & t ! oxidation ( *loride ions to *lor9e is also a rev]sible process1 #b ,cl ,cl#b4 ,we w deal fir/1 9 "s detail1 ) ! action ,fe#c ,fe#b4 ,= ?is rev]sible action we h an equilibrium con/ant#eda ,fe#b 3 ,fe#c ,k,f]ro1 ,f]ri #ajag1 :i* mu/ be p#bgj tak5 into acc\nt 9 all oxidation & r$uction reactions involv+ ^! ions4#edb ,9 a sy/em conta9+ ! two ions1 ! t5d5cy t[>ds r$uction ( f]ric-ion & ! t5d5cy t[>d oxidation ( f]ro-ion w\ld be directly 9 equilibrium 7i4e4 )\t ! int]v5tion ( o!r oppos$ =ces1 su* z an electric pot5tial1 produc$ by an oppos+ cell or produc$ by an oppos+ action#edc ( o!r compon5ts 9 ! solution7 only :5 ! conc5tration ( f]ro-ion is #ajag times z great z ! conc5tration ( f]ric-ion4 ,if we connect a #j4a-mol> solution ( f]ric *loride ) a #j4a-mol> solution ( f]r\s *loride1 by means ( a salt bridge & a pair ( plat9um electrodes dipp+ into ! solutions & connect$ ) ! voltmet] 7see p4 #bec71 a curr5t is produc$1 ! positive curr5t ent]+ ! voltmet] f ! electrode plac$ 9 ! f]ric *loride solution 7exp474 ,x is evid5t t1 9 ! ef=t to e/abli% equilibrium1 f]ric ions 9 ! f]ric *loride solution are r$uc$ at ! exp5se ( ! oxidation ( f]r\s ions 9 ! f]r\s *loride solution4 ,if we consid] only ! ratio ( ! conc5tration ( ! f]ro-ion to t ( ! f]ric-ion 9 ea* ( ! salt solutions & leave out ( consid]ation1 = ! mom5t1 o!r1 second>y1 electrical =ces1#edd x is cle> t ! ratio p#bga ,fe#ba 3 ,fe#ca 9 ! f]r\s salt solution1 consid]$ by itself1 is f> clos] to ! po9t ( equilibrium#ede ?an ! ratio ,fe#bb 3 ,fe#cb 9 ! f]ric *loride solution1 9 :i* ! conc5tration ( f]ric-ion is enorm\sly great] ?an t ( f]ro-ion1 :ile ! equilibrium con/ant dem&s t ! f]ro-ion %\ld be 9 great excess4 ,! /ronge/ t5d5cy to *ange mu/ be t[>d a r$uction ( ! conc5tration ( ! f]ric-ion 9 ! solution ( f]ric *loride1 :i* is 9 agreem5t ) ! obs]v$ direction ( ! curr5t4 ,equilibrium1 x may be add$1 w be rea*$ :5 ! ratio ( ! conc5tration ( f]ro-ion to t ( f]ric-ion is ! same 9 bo? solutions4#edf ,! addition ( potassium fluoride to ! f]ric *loride solution conv]ts ! f]ric-ion into ! r /able complex f]rifluoride-ion ,fe,f#fc1 ^: potassium salt ,k#c;,fe,f#f is =m$4 ,! p#bgb conc5tration ( f]ric-ion be+ decid$ly r$uc$1 ! sy/em mu/ be ne>] to ! condition ( equilibrium1 ! pot5tial mu/ fall 7exp474 ,x is aga9 evid5t 7p4 #bee7 t ! oxidiz+ ag5t is cle>ly ! f]ric-ion1 & n ! total quantity ( ! f]ric salt 9 ! solution4 ,int5sity ( ,reactions4--,vice v]sa1 any oxidiz+ ag5t1 :i* has ! p[] to oxidize f]ro-ion to f]ric-ion1 does s ! m readily & vigor\sly1 ! m completely any f]ric-ion1 pres5t or =m$1 is suppress$4 ,if f]r\s sulphate is add$ to a solution ( silv] nitrate1 a sl[#edg r$uction ( ! silv]-ion1 & oxidation ( ! f]ro-ion1 takes place accord+ to ,fe#b ,ag ,fe#c ,ag 4 ,n[1 if a little potassium fluoride is add$ to ! mixture1 s z to suppress ! f]ric-ion1 :i* is always pres5t1 by contam9ation1 9 ! orig9al f]r\s sulphate solution1 & :i* is =m$ 9 ! action by ! silv] nitrate1 ! oxidation ( ! f]r\s salt & ! precipitation ( metallic silv] is v mu* accel]at$1#edh & a heavy black precipitate ( silv] is =m$ in/antly 7exp474 ,! exp]im5t is an illu/ration ( ! rle ( pot5tial 9 oxidation-r$uction reactions1 ! pot5tial & ! r$uc+ p[] ( f]ro-ion be+ decid$ly dim9i%$ by ! pres5ce ( its oxidation product1 ! f]ric-ion4#edi ,x is also a fur!r illu/ration ( ! rle ! ions play 9 ^! actions1 ! total am\nt ( f]ric salts n be+ *ang$ by ! introduction ( ! fluoride1 :i* simply suppresses f]ric ions4 ,r$uction ( ,f]ric ,salts by ,iodides4--,9 ! /udy ( ! oxidation ( ! f]ro-ion & ! r$uction ( ! f]ric-ion1 we p#bgc h ?us f> consid]$ only ! rev]sible t5d5cies ( ! two ions to *ange into ea* o!r1 t5d5cies :i* w\ld be directly balanc$1 9 a giv5 solution1 )\t ! int]v5tion ( o!r =ces1 :5 ! ratio ( ! conc5trations ( ! ions is t ( ! equilibrium con/ant1 #ajag4 ,9 reactions involv+ ! oxidation ( a f]r\s salt1 we h to deal1 h[ev]1 9 exactly ! same way1 ) ! rev]sible t5d5cy ( ! oxidiz+ sub/ance to act z oxidiz+ ag5t1 &1 simil>ly1 9 e r$uction ( a f]ric salt1 we h to deal also ) ! rev]sible t5d5cy ( ! r$uc+ ag5t to act z su*4 ,9 ord] to rea* "s def9ite conceptions z to ! influ5ces ( ^! conflict+ t5d5cies1 we %all consid]1 next1 ! r$uction ( f]ric salts by iodides1 & !n contra/ ?is r$uction ) ! action ( *lorides on f]ric salts1 & we %all ?us complete ! /udy ( ?is action 7see p4 #bfi74 ,= ! r$uction ( f]ric salts by iodides 7p4 #bea71 we h to consid] ! rev]sible t5d5cy ( iodide-ion to =m iod9e & to be =m$ f iod9e3 #b ,i ,i#b4 ,! con/ant#eej ,k,i1 ,iod9e = ! equilibrium ratio ,i#b _/ ,i#b is #e4f;,e#bi at #be4 p#bgd ,! r$uction ( f]ric salts by iodides is a rev]sible reaction3 #b ,fe#c #b ,i #b ,fe#b ,i#b1 & ! ultimate condition ( equilibrium w dep5d on ! values ( ! con/ants1 ,k,f]ro1 ,f]ri & ,k,i1 ,iod9e1 & on ! conc5trations ( ! compon5ts us$4 ,= ! condition ( equilibrium we h ,fe#cb ,i#b _/ 7,fe#bb ,i#b7 ,keq1 & = ?is con/ant ! relation#eea ,keq ,k,i1 ,iod9e _/ 7,k,f]ro1 ,f]ri7#b #e4f;,e#bi _/ 7#ajag7b #e4f _/ #aje p#bge c be e/abli%$4 ,x is evid5t1 f ! value ( ! con/ant1 t ! *ief t5d5cy ( ! rev]sible reaction w be t[>d ! r$uction ( ! f]ric ions & ! lib]ation ( iod9e1 :i* is 9 accord ) exp]i5ce 7exp41 p4 #bea74 ,x is int]e/+ to note1 aga91 t ! r$uction ( ! f]ric salt dep5ds on ! r$uction ( ! f]ric-ion3 ! f]ric-ion may be suppress$1 ) ! aid ( potassium fluoride 7see p4 #bee71 & ! addition ( potassium iodide to a mixture ( f]ric *loride & potassium fluoride leads to ! =mation ( traces1 only1 ( free iod9e 7exp474 ,action ( ,*lorides on ,f]ric ,salts4--,n[1 :5 a *loride is us$ 9 place ( an iodide1 we h to d ) an ion1 ,cl1 :i* has an enorm\s aff9ity = its *>ge1 z comp>$ ) t ( iodide-ion4 ,! equilibrium relation = ! rev]sible reaction #b ,cl ,cl#b has ! =m ,cl#b 3 ,cl#b ,k,cl1 ,*lor9e1 & ! value#eeb ( ! con/ant is #b;,e#fj4 ,= ! reaction ( *loride-ion on f]ric-ion we w\ld h1 z 9 ! case ( ! action ( iodide-ion1 #b ,fe#c #b ,cl #b ,fe#b ,cl#b & ,fe#cb ,cl#b _/ 7,fe#bb ,cl#b7 ,keq4 ,= ?is equilibrium con/ant we h ! relation1 z det]m9$ above 7p4 #bgd71 ,keq ,k,cl1 ,*lor9e _/ 7,k,f]ro1 ,f]ri7#b 7#b;,e#fj7 _/ 7#ajag7b #b;,e#bf4 p#bgf ,x is evid5t1 f ! value ( ! equilibrium con/ant1 t ! action ( *loride-ion on f]ric-ion mu/ result quantitatively s diff]5tly f ! action ( ! analog\s iodide-ion 7p4 #bge71 t ! net qualitative results are entirely dissimil>4 ,:]eas 9 ! case ( ! iodide1 lib]ation ( iod9e & r$uction ( ! f]ric-ion are b\nd to be ! *ief & obvi\s actions1 9 ! case ( ! *loride-ion1 on ! o!r h&1 ! equilibrium con/ant dem&s t !re %\ld be no appreciable r$uction ( ! f]ric-ion or lib]ation ( *lor9e--:i* is 9 accordance ) our exp]i5ce 7exp41 p4 #bef74 ,x is notewor?y1 h[ev]1 t ! equilibrium relations dem& t at lea/ traces ( *lor9e be lib]at$1 & traces ( f]r\s salt be =m$1 s9ce nei!r ,fe nor ,cl#b may h ! value #j4 ,if we add "s sodium *loride to a solution ( sodium sulphate1 connect$ electrically1 9 ! usual way1 ) a solution ( f]ric sulphate1 a v slight mom5t>y curr5t is produc$ 7exp474 ,! lib]ation ( ! fir/ traces ( *lor9e & ( f]ro-ion on ! electrodes is necess>y1 & also suffici5t1 to satisfy ! conditions = equilibrium z express$ by ! con/ant1 until diffusion f ! electrodes removes ^! traces4 ,summ>y4--,we f9d1 ?us1 t ! g5]al pr9ciple ( ! quantitative relations gov]n+ oxidation & r$uction gives u ! means ( int]pret+ ! diff]5ces 9 results 9 7qualitatively7 simil> comb9ations1 :i*1 qualitatively1 might lead to an oxidation-r$uction reaction1 & :i*1 9 c]ta9 cases1 d produce su* reactions 7f]ric-ion ) iodide-ion71 & 9 o!r cases d n 7f]ric-ion ) *loride-ion74 ,,footnotes3 #ead ,! oxidation by *lor9e may also be repres5t$ on ! basis ( ! conception t ! *lor9e molecule conta9s a positive & a negative *lor9e atom1 ,cl,cl4 7,vide ,w4 ,a4 ,noyes1 ,j4 ,am4 ,*em4 ,soc41 #bc1 #dfj 7#aija72 ,/ieglitz1 ibid41 #bc1 #gif 7#aija72 ,wald51 ,z4 phys4 ,*em41 #dc1 #che 7#aijc72 ,j4 ,j4 ,?omson1 ,corpuscul> ,!ory ( ,matt]1 p4 #acj 7#aijg774 ,we may consid] ! action to take place z foll[s3 #b ,fe#b ,cl #b ,fe#c ,cl4 #eae is us$ to indicate an electron4 #eaf ,! :ole device is an adaptation ( ,o/wald's ,*emomet] see ,z4 phys4 ,*em41 #ae1 #cii 7#ahid74 ,x has be5 f\nd be/ to conv]t a ,we/on voltmet] into a lecture table app>atus by l5g!n+ its index to #aj in*es1 ) ! aid ( a v light1 holl[ alum9ium wire c>ry+ an index & play+ ov] a scale #aj in*es wide1 drawn on glass & divid$ into #aej divisions4 ,! scale is illum9at$ by means ( five small "o-c&le-p[] lamps4 ,! :ole is encas$ 9 a simple wood5 frame4 ,! voltmet] %[s a range ( #j4g volt1 b1 on acc\nt ( its l[ resi/ance 7#gh ohms71 x is us$ only = qualitative purposes & does n regi/] ! true pot5tials1 quantitatively4 7,su* adaptations ( ,we/on voltmet]s may be pur*as$ f ! ,we/on ,electrical ,in/rum5t ,co41 or a simil> in/rum5t obta9$ f ,h>tmann & ,braun1 ,frankfurt a_/,m1 ,g]many47 #eag ,*emical ,action at a ,di/ance1 ,o/wald1 ,z4 phys4 ,*em41 #i1 #edj 7#ahib74 #eah ,pet]s1 ,z4 phys4 ,*em41 #bf1 #bbi 7#ahih74 #eai ,see bel[1 9 reg>d to ! quantitative relations = reactions ( ?is nature4 #ebj ,,exp4 ,f]ric sulphate solution is te/$ ) a f]ricyanide4 #eba ,rigor\s quantitative exam9ation ( ! relations %[s 7p4 #bge7 t ^! r$uctions & oxidations d take place1 b equilibrium is rea*$ :5 !y h proce$$ to s slight an ext5t1 t1 qualitatively1 !y are n always obvi\s or disc]nible4 #ebb ,a *ange 9 ! nature ( ! solv5t *anges ! value ( ! equilibrium con/ant1 j z x *anges ! ionization con/ant ( electrolytes4 ,see p4 #fa & see rem>ks by ,sackur1 ,z4 ,elektro*em41 #aa1 #chg 7#aije74 #ebc ,= exce$+ly ?9 films ( copp] we _c make ?is assumption1 & = su* films ! conclusions1 t foll[1 are1 9 fact1 f\nd n to hold4 7,ov]beck4 ,vide ,le ,blanc1 ,electro*emi/ry1 p4 #beb 7#ahif774 #ebd ,z4 phys4 ,*em41 #d1 #abi 7#ahhi74 #ebe ,! values ( ?is & simil> equilibrium con/ants are d]iv$ by means ( ,n]n/'s =mula 7see bel[7 = ! pot5tial diff]5ce betwe5 an elem5t & solutions ( its ions4 ,! d]ivation involves ! assumption t ?is =mula expresses correctly ! relation betwe5 ! pot5tial *ange & ! conc5tration *ange at all conc5trations4 ,?is assumption appe>s to be ju/ifi$ by all exp]im5tal indications ?us f> obs]v$4 ,! con/ants are ( importance1 prim>ily1 = ! calculations :i* c be made ) _! aid 7see bel[71 & may1 cons]vatively1 be consid]$ to be ess5tially calculation factors 7,re*5grss51 accord+ to ,hab]4 ,see pp4 #bcb-g1 ,*apt] ,,xii74 ,! con/ants may be express$1 z 9 ! text1 9 t]ms ( 7mol>7 conc5trations ( ! ions1 or 9 t]ms ( ! osmotic pressures ( ! ions1 a mol> solution at #j produc+ an osmotic pressure ( #bb4d atmosph]es4 ,:]e osmotic pressure & conc5tration are n /rictly proportional 7e4g4 = conc5trat$ solutions71 ! osmotic pressure1 r ?an ! conc5tration1 is ! det]m9+ factor &1 :5 kn[n1 is us$ 9 exact calculations4 ,! plan1 pursu$ 9 ! text1 is adopt$ 9 ord] to express ^! con/ants 9 ! t]ms us$ = all ! o!r equilibrium con/ants4 ,x %\ld be recall$ 7e4g4 p4 #cj7 t 9 calculations1 9 g5]al1 :]e pressure & conc5tration are n /rictly proportional1 ! pressure is ! det]m9+ factor4 ,a ?ird me?od ( express+ ! solution-t5sion relations consi/s 9 giv+ ! pot5tial diff]5ces1 :i* exi/ betwe5 elem5ts & solutions ( _! ions1 9 :i* ! ions h unit 7mol>7 conc5tration4 ,^! pot5tial diff]5ces are functions ( ! solution-t5sion con/ants1 z w be discuss$ bel[1 & ! con/ants1 9 t]ms ( conc5trations or osmotic pressures1 may be easily calculat$1 f ! pot5tial diff]5ces1 ) ! aid ( ?is function 7see bel[1 & see ! table at ! end ( ,*apt] ,,xv74 #ebf ,accord+ to ,wilsmore's tabulation 7,z4 phys4 ,*em41 #cf1 #ib 7#aija771 ! pot5tial diff]5ce ,cu1 ,cu#b ( copp] aga9/ a #j4e mol> solution ( cupric sulphate1 9 :i* ,cu#b #j4aa1 is #j4ehd volt4 ,ins]t+ ^! values = ,cu#b & ,cu1 ,cu#b 9 ! equation ,cu1 ,cu#b 7#j4jege _/ #b7 log7,cu#b _/ ,k7 7see bel[7 & solv+ ! equation = ,k1 we f9d ,k #h;,e#bb4 ,= ,cu#b #j4bd1 ,cu1 ,cu#b is #j4eid volt & ,k #h;,e#bb4 ,9 reg>d to ! conv5tion det]m9+ ! signs us$ 79 ! pres5t case ,cu1 ,cu#b is positive71 see ! footnote bel[1 p4 #bfb1 & 9 reg>d to ! def9ition ( z]o pot5tial1 to :i* ! pot5tial diff]5ces us$ 9 ?is book ref]1 see ! table & summ>y at ! end ( ,*apt] ,,xv4 #ebg ,n]n/1 loc4 cit41 p4 #aea4 #ebh ,9 o!r words1 ! great] ! conc5tration ( cupric-ion1 ! great] its osmotic pressure mu/ be1 & ! repell+ electric =ce1 requir$ to ov]come ! pressure ( ! cupric-ion1 w\ld be correspond+ly great]4 #ebi ,cf4 ,n]n/1 ,!oretical ,*emi/ry 7#aijd71 pp4 #gbj-gbc1 9 reg>d to ! d]ivation & ! g5]al =m ( 8 =mula4 #ecj ,= elem5ts t =m negative ions1 e4g4 = *lor9e1 brom9e1 oxyg51 etc41 ! equation reads 7see pp4 #bgc1 #bge & ! table at ! end ( ,*apt] ,,xv73 ,elem41 ,electrolyte 7#j4jege _/ v7 log7,c _/ ,k74 ,note ! *ang$ sign ( ! expression on ! "r4 ,! diff]5ce 9 sign expresses ! fact t1 :5 negative ions dis*>ge on an electrode1 !y r5d] x negative1 & :5 !y are =m$ by an electrode1 !y leave ! latt] positive2 = positive ions1 x w be recall$1 ! conditions are j ! rev]se 7see above74 ,:]e a soluble elem5t 7e4g4 *lor9e7 or a solution ( a metal 7e4g4 sodium amalgam7 is us$ z an electrode1 its conc5tration1 9 g5]al1 is n con/ant1 z 9 ! case ( a pure1 solid metal l copp] 7p4 #beh74 ,9 su* cases1 ! quantity 9 ! d5om9ator ( ! ratio 9 ! log>i?m _c be express$ by a con/ant ,k1 b is express$ by ,k ,c,elem5t1 ,c,elem5t be+ us$ to indicate ! conc5tration ( ! elem5t 9 ! exp]im5t 9 "q4 #eca ,! conv5tion1 adopt$ 9 ! text1 = ! use ( ! positive & negative signs 9 express+ pot5tials1 is t propos$ by ,lu!r 7cf4 ,le ,blanc's ,lehrbu* d] ,elektro*emie 7?ird edition71 p4 #bab74 ,! sign always d5otes ! "* ( ! *>ge on ! fir/ compon5t writt5 9 ! subscript to 4 ,?us1 = a copp] plate 9 contact ) a solution ( cupric sulphate1 :5 ,c ,k1 ! log>i?m1 log7,c _/ ,k71 has a positive value & ,cu1 ,cu,s,o#d is positive1 :i* means t ! metal w be positive1 ! electrolyte negative4 ,= in/ance1 = ,cu#b #a1 ,cu1 ,cu,s,o#d is f\nd to be #j4fjf 7see ! table at ! end ( ,*apt] ,,xv74 ,cu1 ,cu,s,o#d ,cu,s,o#d1 ,cu4 ,by ?is use ( ! signs "o is nev] 9 d\bt z to _! mean+4 ,un=tunately1 widely diff]5t def9itions ( ! signs h be5 us$ 7cf4 ,le ,blanc1 ,electro*emi/ry 7#ahif71 pp4 #bji1 #bai1 & ,lehfeldt1 ,electro-,*emi/ry 7#aijd71 p4 #aei74 ,c>e mu/ be tak51 9 us+ ! data ( orig9al pap]s1 to be in=m$ z to ! def9ition us$4 ,9 accordance ) ! conv5tion z to signs1 adopt$ 9 ?is book1 ! ratio ( conc5trations 7,c _/ ,k71 us$ 9 ! log>i?m ( ,n]n/'s =mula1 is ! reciprocal ( ! ratio usually giv54 ,! *ange has be5 made 9 ord] t ! algebraic signs ( ! values obta9$ f ! application ( ! =mula %\ld be ! same z ^? obs]v$ 9 ! exp]im5tal arrangem5ts1 z dem&$ by ! conv5tion4 #ecb ,:5 two electrodes are comb9$ to =m an electric cell or c\ple1 ! pot5tial diff]5ce ( ! c\ple is always ! 7algebraic7 diff]5ce ( ! two individual electrode pot5tials1 & h5ce ^! are subtract$ f ea* o!r 7algebraically74 ,! electrode ( ! fir/ t]m ( ! diff]5ce 7! m9u5d7 is nam$ fir/ 9 ! subscript ( ! pot5tial ( ! c\ple2 !n ! sign ( ! diff]5ce repres5ts ! "* ( ! *>ge on t electrode1 9 agreem5t ) ! conv5tion 7see footnote #b1 p4 #bfa74 ,9 illu/ration3 two copp] electrodes may be tak51 ea* ( :i*1 consid]$ by itself1 c>ries a positive *>ge1 because ! conc5trations ( ! cupric-ion 9 ! solutions ba?+ !m are bo? great] ?an ,k2 :5 !y are comb9$1 ea* ( ! two electrodes w t5d to s5d a positive curr5t1 9 opposite directions1 into ! metal connect+ !m4 ,b ! pot5tial ( ! electrode ) ! heavi] *>ge 7! "o dipp+ into ! solution conta9+ ! great] conc5tration ( cupric-ion7 w ov]come ! pot5tial ( ! o!r electrode1 & ! curr5t w fl[1 ?r\gh ! connect+ metal1 ) a pot5tial t repres5ts ! diff]5ce betwe5 ! two values4 ,if ! electrode ( ! m conc5trat$ solution is nam$ fir/ 9 ! subscript ( ! pot5tial ( ! c\ple1 its individual electrode-pot5tial appe>s z ! fir/ t]m ( ! diff]5ce 7! m9u5d7 & is r$uc$ by ! value ( ! electrode-pot5tial ( ! second electrode2 z ?is is num]ically small] ?an ! value ( ! m9u5d1 ! diff]5ce w be positive1 %[+ t ! electrode 9 ! /rong] solution1 nam$ fir/ 9 ! subscript ( ! pot5tial diff]5ce ( ! c\ple1 c>ries a positive *>ge4 ,fur!r1 if ! second electrode dips into a solution1 9 :i* ! conc5tration ( ! cupric-ion is small] ?an ,k1 ! log>i?mic expression = its electrode-pot5tial w be f\nd to give a negative value2 & ! 7algebraic7 subtraction ( ?is negative quantity f ! electrode-pot5tial ( ! fir/ electrode w give a l>g] pot5tial diff]5ce1 = ! c\ple1 ?an t possess$ by ! fir/ electrode alone--all ( :i* agrees ) ! exp]im5tal results1 :5 su* comb9ations are made4 ,:]e negative elem5ts are conc]n$1 ! same conv5tion holds1 b ! log>i?mic expression = ! pot5tial ( su* an electrode c>ries a negative sign 7see footnote #a1 p4 #bfa71 :i* mu/ be ins]t$1 algebraically1 :5 ! expression is us$ z a t]m 9 ! diff]5ce "u discussion4 #ecc ,if ,c ,c1 ! log>i?m w be positive & ,cu1 ,cu w h a positive value1 :i* means t ! copp] plate1 ,cu1 :i* is nam$ fir/ 9 ! subscript to 1 w be *>g$ positively1 :5 ! sy/em works4 ,if ,c ,c1 ! log>i?m w be negative1 :i* means t ! fir/ plate1 ,cu1 m5tion$ 9 ! subscript1 w receive a negative *>ge1 :5 ! sy/em works4 ,! sign is !re=e int5d$1 by ! conv5tion adopt$ 7p4 #bfa71 to express any result = ! work+ sy/em1 irrespective ( ! *>ge on ! individual plates be=e !y are comb9$4 ,= in/ance1 = ,c #a & ,c #ajaj1 bo? plates are positive1 be=e !y are connect$ ) ea* o!r1 s9ce 9 ea* case ,c ,k1 & ,cu1 ,cu,x 7#j4jege _/ #b7 log7,c _/ ,k7 a positive value4 ,:5 ! plates are comb9$1 we f9d f ,cu1 ,cu 7#j4jege _/ #b7 log7,c _/ ,c7 t ! fir/ plate1 dipp+ 9 ! m conc5trat$ solution ( cupric-ion1 is positive1 :i* is confirm$ by exp]im5t4 #ecd 7#a _/ #aj7-mol> cupric sulphate1 #ajj c4c41 conta9+ "s sodium sulphate or nitrate1 to r$uce ! resi/ance1 is a conv5i5t conc5tration4 #ece ,! copp] plate is be/ fre$ f adh]+ sulphide by means ( a /rong cyanide solution1 & re-introduc$ into ! solution4 #ecf ,k/]1 ,z4 ,elecktro*em41 #d1 #aaj & #ejc 7#ahig74 #ecg ,9 a solution ( z9c sulphate 9 :i* ,zn#b #j4aad1 ! pot5tial ,zn1 ,zn,s,o#d #j4ead 7! m9us sign indicates t ! metal nam$ fir/ 9 ! subscript has a negative *>ge74 ,ins]t+ ! values = ,zn#b & ,zn1 ,zn,s,o#d 9 ! g5]al equation giv5 on p4 #bfa1 & solv+ = ,k1 we f9d ,k #ajag4 ,= ,zn#b #j4jbb & ,zn1 ,zn,s,o#d #j4ece1 we f9d ,k #ajaf4h4 7,cf4 ,wilsmore's tables1 loc4 cit47 #ech ,equilibrium w be e/abli%$ :5ev] ! pot5tial ( ! sy/em is equal to #j4 ,! pot5tial ( ! sy/em may be calculat$ accord+ to ! equation 7see footnote #a1 p4 #bfb7 ,cu1 ,zn ,cu1 ,cu,s,o#d ,zn1 ,zn,s,o#d 7#j4jege _/ #b7 7log7,cu#b _/ ,k,cu7 log7,zn#b _/ ,k,zn774 ,! pot5tial ,cu1 ,zn is #j :5ev] ,cu#b _/ ,k,cu ,zn#b _/ ,k,zn1 i4e4 :5 ,zn#b _/ ,cu#b ,k,zn _/ ,k,cu4 ,= ions ( diff]5t val5ce1 su* z silv] & cupric ions1 ! equilibrium equation assumes a some:at less simple =m4 ,= ,cu #b ,ag #b ,ag ,cu#b1 we h ,ag#b _/ ,cu#b 7,k,ag7#b _/ ,k,cu4 #eci ,vide ,o/wald's ,lehrbu* d] allgeme95 ,*emie1 #b;d ,ed41 ,vol4 ,,ii1 p4 #hgd1 = ! hi/orical data on ?is action4 ,vide ,k/]'s exp]im5ts1 ,z4 ,elektro*em41 #d1 #ejc 7#ahig74 #edj ,see ! footnote1 p4 #bfg1 9 reg>d to ! =m ! equilibrium ratio assumes :5 metals produc+ ions ( diff]5t val5ce are us$4 #eda ,! value ( ! con/ant is calculat$ f ! data giv5 by ,pet]s1 ,z4 phys4 ,*em41 #bf1 #aic 7#ahih74 #edb ,! fact t ?is equilibrium relation has be5 prov$ to hold = ! action ,fe#b ,fe#c & t x mu/ be tak5 into acc\nt 9 all oxidation-r$uction reactions involv+ ^! ions1 9 no wise excludes ! possibility t o!r equilibrium relations c also exi/ betwe5 f]r\s & f]ric comp\nds4 ,= in/ance1 f]r\s hydroxide ,fe7,,oh7#b may well h a *>act]i/ic t5d5cy ( its own to assume a fur!r positive *>ge 7lose an electron7 accord+ to ,fe7,,oh7#b ,fe7,,oh7#b1 ! pot5tial ( :i* action may1 "u giv5 conditions1 be a ma9 det]m9+ factor 9 ! c\rse ( an action1 e4g4 9 alkal9e mixtures4 ,x is n impossible1 ev51 t we also mu/ consid] negative ions ,fe,o#bb & _! t5d5cy to be oxidiz$4 ,evid5ce w\ld sugge/ t f]r\s hydroxide1 or its negative ion ,fe,o#bb1 may h1 inde$1 a v great t5d5cy to be oxidiz$1 possibly mu* great] ?an ! t5d5cy ( ,fe#b to =m ,fe#c4 7,cf4 ,man*ot1 ,z4 anorg4 ,*em41 #bg1 #dai 7#aija71 & ,mc,coy & ,bunzel1 ,j4 ,am4 ,*em4 ,soc41 #ca1 #cgj 7#aiji774 ,clos] inve/igations ( ^! relations1 f a quantitative viewpo9t1 w\ld probably det]m9e ?is "q & br+ exce$+ly important relations to light4 #edc ,e4g4 by ! pot5tial ( ! action ,cl#b #b ,cl4 #edd ,! pot5tial ( a solution ( ! iron salts is giv5 by #j4jeh log7#ajag ,fe#c _/ ,fe#b74 ,9 a solution ( a f]ric salt1 if ,fe#b #j1 ! pot5tial w\ld obvi\sly be 1 :i* c\ld n pres5t a condition ( equilibrium4 ,equilibrium is e/abli%$ 9 su* a solution1 z w be %[n fur!r on 9 ! text1 by ! lib]ation ( *lor9e & ! =mation ( f]ro-salt1 accord+ to #b ,fe#c #b ,cl #b ,fe#b ,cl#b1 until ! pot5tial1 result+ f ! t5d5cy ( *lor9e to =m *loride-ion1 j balances ! t5d5cy ( ! f]ric-ion to =m f]ro-ion4 ,b :5 a f]ric *loride solution is us$ z ! s\rce ( supply ( positive electricity1 z 9 ! exp]im5t describ$ 9 ! text1 bo? ! f]ric-ion & ! *lor9e t5d to *>ge ! plat9um electrode ) positive electricity & to rev]t to a condition ( equilibrium 9 ref]5ce to _! individual con/ants4 ,! relations are mu* l ^? betwe5 a cupric salt solution & a copp] plate3 if ,cu#b ,k,cu#b1 equilibrium w be e/abli%$1 z we h se51 by ! positive *>g+ ( ! plate 9 suffici5t degree to oppose ! t5d5cy ( ! cupric-ion to dis*>ge 7see p4 #bei74 ,b :5 ! solution & plate are us$ z ! s\rce ( supply = an electric curr5t 7p4 #bfd71 bo? ! positive *>ge on ! plate1 & ! t5d5cy ( ! cupric-ion to dis*>ge & acquire ! conc5tration ,cu#b ,k,cu#b1 w supply ! positive curr5t4 ,9 calculations we ignore ! positive *>ge already deposit$ on ! plate & deal only ) ! conc5tration ( ,cu#b4 ,! *lor9e1 lib]at$ 9 a solution ( f]ric *loride1 plays practically ! same rle z does ! copp] plate 9 a cupric salt solution1 & x c be ignor$ 9 ! discussion ( ! comb9ation describ$ 9 ! text4 ,9 a f]r\s salt solution1 9 a simil> mann]1 "s f]ric-ion mu/ always be =m$ by lib]ation ( hydrog5 7see p4 #bhb71 until equilibrium is rea*$ accord+ to #b ,fe#b #b ,h #b ,fe#c ,h#b4 ,hydrog5 plays "h ! same rle z *lor9e does 9 ! f]ric *loride solution4 #ede ,! condition = equilibrium is ,fe#b 3 ,fe#c #ajag1 9 a solution consid]$ = itself4 #edf ,?is ratio ne$ n be #ajag1 s9ce we h two solutions comb9$ ) ea* o!r & ! total pot5tial w be express$ by3 #a #b #j4jeh 7log7#ajag ,fe#ca _/ ,fe#ba7 log7#ajag ,fe#cb _/ ,fe#bb77 #j4jeh log7,fe#ca ,fe#bb _/ 7,fe#ba ,fe#cb774 ,equilibrium is rea*$ :5 ! total pot5tial is #j4 ,!n ,fe#ca ,fe#bb _/ 7,fe#ba ,fe#cb7 #a & ,fe#ba _/ ,fe#ca ,fe#bb _/ ,fe#cb4 #edg ,9 ord] to h v decid$ diff]5ces 9 ! spe$s ( ! action 9 ! abs5ce & pres5ce ( fluoride1 x is be/ to use an old f]r\s sulphate1 or f]r\s ammonium sulphate1 solution :i* conta9s consid]able f]ric salt4 #edh ,vide ,pet]s1 loc4 cit41 p4 #bcf4 #edi ,o/wald ,lehrbu* d4 allgem4 ,*em41 #b;d ,ed41 ,,ii1 #hhc 7#ahic71 fir/ emphasiz$ ! fact t pot5tial diff]5ces are a measure ( oxidiz+ & r$uc+ p[]s4 #eej ,! con/ant is calculat$ f ! data ( ,k/] & ,crotog9o on ! pot5tial ( solutions ( iod9e 9 potassium iodide ,z4 anorg4 ,*em41 #bc1 #hh 7#aijj74 ,ow+ to ! =mation ( complex ions ,i#c1 = :i* due all[ance has n be5 made 9 ! calculation1 & ow+ to "s unc]ta9ty z to ! vague def9ition ( ! conc5tration ( iod9e us$1 ! e/imation ( ! con/ant c only be consid]$ a r\gh "o4 ,! value giv5 expresses ! ord] ( ! equilibrium ratio suffici5tly well = our pres5t purposes4 ,9 a rec5t pap]1 ,bray & ,mac,kay ,j4 ,am4 ,*em4 ,soc41 #cb1 #iad 7#aiaj7 h det]m9$ ! con/ant = ! =mation ( ! complex ion accord+ to ,i#c ,i#b ,i1 :i* might be us$ to correct ! data ( ,k/] & ,crotog9o2 b 9 view ( o!r unc]ta9ties & inaccuracies1 ! correction has n be5 consid]$ advisable4 ,sev]al relat$ me?ods may be us$ to calculate ! equilibrium con/ant = ,i#b 3 ,i#b ,k f ! data ( ,k/] & ,crotog9o4 ,p]haps ! simple/ me?od is ! foll[+3 ,a solution ( iod9e 7,i #a _/ #cb normal1 & !re=e ,i#b #a _/ #fd mol>7 9 #a_/h mol> potassium iodide1 9 :i*1 ! degree ( ionization be+ tak5 into acc\nt1 ,i #j4aji1 0 obs]v$ to %[ a pot5tial ,i#b1 ,i #j4hfj 7! conv5tion z to signs1 discuss$ on p4 #bfa1 is us$ "h & ! pot5tial1 obs]v$ aga9/ a s-call$ calomel electrode1 is r$uc$ to ! s-call$ absolute pot5tial2 cf4 ,le ,blanc1 ,lehrbu* d] ,elektro*emie1 p4 #bad74 ,n[1 !re mu/ be a c]ta9 conc5tration ( iodide-ion1 :i* we w call ,c1 ) :i* iod9e ( ! above conc5tration w\ld be directly 9 equilibrium & w\ld give no pot5tial at all 7cf4 pp4 #bfa & #beh 9 reg>d to copp]74 ,) a *ange 9 ! conc5tration ( ! iodide-ion1 a pot5tial w\ld be produc$ accord+ to ,i#b1 ,i #j4jege log7,c _/ ,i74 ,?is relation is ( exactly ! same nature z t develop$ = ! pot5tial ( copp] plates1 imm]s$ 9 solutions ( cupric-ion ( diff]5t conc5trations 7b see footnote #a1 p4 #bfa1 conc]n+ ! sign ( ! new relation74 ,9 ! pres5t case1 we are deal+ ) unival5t ions1 ,i1 9 place ( bival5t ions ,cu#b1 & ! factor #j4jege is us$ in/ead ( #j4jege _/ #b 7see p4 #bfa74 ,if we ins]t ! obs]v$ values1 ,i #j4aji & #j4hfj1 ( ! exp]im5t describ$ above1 into ! equation ,i#b1 ,i #j4jege log7,c _/ ,i7 & solve ! equation = ,c1 we f9d ,c #ajad4 ,t means1 #a _/ #fd mol> iod9e w\ld be directly 9 equilibrium ) a conc5tration ( iodide-ion #ajad 7if ?is value is ins]t$ = ,i 9 ! log>i?mic equation1 ! pot5tial is f\nd to be #j74 ,= ! condition ( equilibrium = ,i#b #b ,i1 accord+ to ,i#b 3 ,i#b ,k1 we h !n 7#ajad7b 3 7#a _/ #fd7 ,k #f4d;,e#bi4 ,simil>ly1 = ,i #j4aji & ,i#b #a _/ #eab ! pot5tial #j4hca is obs]v$1 & ! equilibrium con/ant is f\nd to be #e4a;,e#bi4 ,:5 ,i #j4aji & ,i#b #a _/ #abh1 ! pot5tial is #j4hej & ! con/ant is calculat$ to be #e4c;,e#bi4 ,! mean value = ,k is #e4f;,e#bi4 ,9 ^! calculations1 ! =mation ( ions ,i#c1 affect+ ! values = ,i & ,i#b1 has n be5 consid]$1 & !re is "s d\bt :e!r ! conc5trations ( iod9e1 giv5 by ,k/] & ,crotog9o1 d n repres5t ,i#b r ?an ,i1 z assum$ 9 ! calculations4 ,if ! =m] be ! case1 ! mean value ( ! above exp]im5ts w\ld be #b4h;,e#bi4 ,! value1 us$ 9 ! text1 is consid]$ suffici5tly accurate = ! purposes ( ?is book4 #eea ,?is relation ( ! equilibrium con/ant & ! solution-t5sion con/ants may be d$uc$ 9 a mann] simil> to t = ! analog\s equilibrium con/ant = ! oxidation ( z9c by ! cupric-ion1 z giv5 9 footnote #a1 on page #bfg4 ,! exact value ( ! equilibrium con/ant is unc]ta91 s9ce ,k,i1 ,iod9e has n yet be5 det]m9$ ) a suffici5t degree ( accuracy2 b ! value1 us$1 gives ! ord] ( ! con/ant suffici5tly well = our purposes1 especially :5 x is consid]$ 9 connection ) ! con/ant giv5 bel[ = ! same relation1 :5 ! *loride-ion is sub/itut$ = ! iodide-ion4 #eeb ,?is is ! value ( ! con/ant z calculat$ f ! data giv5 by ,wilsmore 7,z4 phys4 ,*em41 #cf1 #ia 7#aijj77 = ! solution-t5sion ( *lor9e "u atmosph]ic pressure at #ah4 ,! calculation may be made exactly z 9 ! case ( ! simil> con/ant = iod9e 7p4 #bgc74 ,!re mu/ be a conc5tration ( *loride-ion1 :i* we w call ,c1 ) :i* *lor9e1 ( "o atmosph]e pressure at #ah1 w\ld be directly 9 equilibrium4 ,! pot5tial ( *lor9e1 aga9/ any o!r conc5tration ( *loride-ion1 w\ld be ,cl#b1 ,cl #j4jege log7,c _/ ,cl74 ,= ,cl #a1 is #a4fid 7see ! table at ! end ( ,*apt] ,,xv71 & ins]t+ ^! values 9 our equation & solv+ x = ,c1 we f9d ,c #b4hh;,e#bi4 ,t means1 t *lor9e1 at #ah & ( atmosph]ic pressure1 w\ld be 9 equilibrium ) *loride-ion ( ! conc5tration giv54 ,s9ce *lor9e1 at ?is temp]ature & pressure1 has a conc5tration ( #a _/ #bc4i moles 7at #ah1 "o mole is conta9$ 9 #bc4i lit]s1 in/ead ( 9 #bb4d lit]s1 at ,o71 we h = ! condition ( equilibrium3 ,cl#b 3 ,cl#b 7#b4hh;,e#bi7b 3 7#a _/ #bc4i7 #b;,e#fj4 ,cl#b repres5ts1 ?us1 9 ! calculation ( ?is con/ant1 ! conc5tration ( *lor9e gas 7see ,*apt] ,,xv conc]n+ gas electrodes7 & n ! conc5tration ( ! dissolv$ *lor9e2 ! latt]1 h[ev]1 is proportional to ! gas conc5tration 7,*apt] ,,vii74 p#bgg ,,*apt] ,,xv ,,oxidation ,,& ,,r$uction4 ,,ii4 ,,oxidation ,,by ,,oxyg51 ,,p]manganates1 ,,etc42 ,,oxidation ,,( ,,organic ,,comp\nds ,we w turn n[ to ! consid]ation ( ! "q1 h[ ! pr9ciples ( ! !ory ( electric oxidation & r$uction may be appli$ to ! mo/ important oxidiz+ ag5t1 oxyg51 & to su* vigor\s & common oxidiz+ ag5ts z p]manganates1 di*romates1 nitric acid1 & simil> sub/ances4 ,oxidation ( ,hydrog5 by ,oxyg54--,! oxidation ( hydrog5 by oxyg5 may be fir/ consid]$1 z repres5t+ a typical &1 9 "s respects1 ! mo/ important case ( oxidation by oxyg54 ,hydrog51 l copp]1 z9c1 & o!r elem5ts1 has a c]ta9 t5d5cy to =m its ion1 ,h1 & ! latt]1 9 turn1 has a t5d5cy to be r$uc$ to hydrog54 ,we may put ,h#b #b ,h & ! condition = equilibrium1 at a giv5 temp]ature1 w be ,h#b _/ ,h#b ,k,h1 ,hydrog54 ,9 ?is equation ,h#b repres5ts ! conc5tration ( ! hydrog5 9 contact ) ! electrode 7see bel[7 & ) ! solution1 & ,h repres5ts ! conc5tration ( hydrog5-ion 9 ! solution ba?+ ! electrode4 ,! ionization ( hydrog51 at a giv5 temp]ature1 dep5ds1 accord+ to ?is equation1 on two v>iables1 ! conc5tration1 or pressure1 ( ! gas & ! conc5tration1 or osmotic pressure1 ( ! hydrog5-ion 9 a giv5 solution4 ,if plat9um gauze1 coat$ ) plat9um black1 is *>g$ ) hydrog51 !n1 ! great] ! pressure ( ! gas1 ! m soluble ! hydrog5 w be 9 ! plat9um 7p4 #aba74 ,su* a *>g$ gauze may be us$ z a hydrog5 electrode 7,fig4 #ac1 p4 #bha71 ! conc5tration ( ! hydrog5 9 :i* is proportional to ! conc5tration1 or pressure1 ( ! hydrog5 gas surr\nd+ x2 ! plat9um w all[ ( ! ready transmission ( electric *>ges f & to ! hydrog5 dissolv$ 9 x4 p#bgh ,! value ( ! con/ant#eec ,k,h1 ,hydrog5 ,h#b _/ ,h#b1 at #ah1 is f\nd to be #e4ee;,e#i1 & hydrog51 at #ah1 "u atmosph]ic pressure1 is directly 9 equilibrium ) hydrog5-ion ( ! conc5tration ,h #a4eb;,e#e4 ,if su* an electrode1 9 contact ) hydrog5 ( atmosph]ic pressure1 is dipp$ into ! solution ( "s neutral salt1 say sodium *loride1 9 :i* ! conc5tration ( ! hydrog5-ion1 =m$ by ! ionization ( wat]1 at #ah1 is #j4i;,e#g1 :i* is less ?an #a4e;,e#e1 ! hydrog5 9 ! electrode mu/ t5d to ionize m rapidly ?an x is =m$ f ! ion1 & ! electrode mu/ receive a negative *>ge1 exactly z 9 ! case ( z9c1 plac$ 9 a z9c sulphate solution4 ,= oxyg5 simil> relations may be develop$4#eed ,we h3 ,o#b #b ,o#b & ,o#bb _/ ,o#b ,k#a4 7#a7 ,if we use ! relation ( ! oxide-ion1 ,o#b1 to ! m /able hydroxide-ion1 ,,ho1 we also h3#eee p#bgi ,,ho#d _/ ,o#b ,k#b ,k,,ho1 ,oxyg5 7#b7 ,! value ( ! con/ant ,k,,ho1 ,oxyg5 is #h4b;,e#di at #ah1 & oxyg5 ( atmosph]ic pressure at ?is temp]ature %\ld be 9 equilibrium ) solutions conta9+ hydroxide-ion at a conc5tration#eef ( #a4cf;,e#ab4 ,an electrode ( plat9um gauze1 *>g$ ) oxyg5 "u atmosph]ic pressure1 :5 dipp$ into ! solution ( a neutral salt1 acquires a v /rong positive *>ge1 ! m9ute conc5tration ( hydroxide-ion1 #j4i;,e#g1 be+ v mu* small] ?an ! value requir$ by ! con/ant1 & ! oxyg5 ioniz+ v mu* m rapidly1 9 consequ5ce1 ?an x is =m$ by ! dis*>ge ( hydroxide ions 7see p4 #bei74 p#bhj ,:5 we comb9e ! hydrog5 & ! oxyg5 electrodes1 dipp+ into a solution ( sodium *loride1 we f9d a curr5t is1 9 fact1 e/abli%$ 7! app>atus discuss$ on p4 #bha is us$71 & x fl[s 9 ! direction anticipat$ f ! above developm5t1 ! positive curr5t ent]+ ! voltmet] f ! oxyg5 electrode4#eeg ,! pot5tial ( ! hydrog5 electrode1 = a con/ant pressure ( hydrog51 is dep5d5t on ! conc5tration ( hydrog5-ion 9 ! solution surr\nd+ ! electrode1 exactly z ! pot5tial ( a copp] plate1 aga9/ a solution ( cupric-ion1 dep5ds on ! conc5tration1 or osmotic pressure1 ( cupric-ion 9 ! solution 9 :i* ! plate is imm]s$4 ,! conc5tration ( hydrog5-ion1 9 ! pres5t in/ance1 is v small 7#j4i;,e#g1 at #ah71 ! solution be+ practically neutral2 b ! addition ( an alkali mu/ r$uce its conc5tration f> bel[ ev5 ?is value1 s9ce = wat] ! product ( ! conc5trations ( hydrog5-ion & hydroxide-ion is a con/ant 7p4 #agf7 & ! increase 9 ! conc5tration ( hydroxide-ion1 produc$ by ! addition ( alkali1 mu/ decrease ! conc5tration ( ! hydrog5-ion proportionally4 ,we w\ld expect1 !n1 t ! pot5tial ( ! hydrog5 electrode mu/ increase1 :5 we add alkali to ! solution surr\nd+ x1 ! hydrog5 n[ ioniz+ aga9/ a mu* small] conc5tration ( its ion4 ,su* is 9 fact ! case 7exp471 & ! increase is f\nd to be subject to a log>i?mic function = ! relation betwe5 pot5tial & ! conc5tration ( ! ion1 simil> to t f\nd to hold = copp] & its ion4#eeh ,9 ! same way1 ! pot5tial ( ! oxyg5 electrode mu/ dep5d on ! conc5tration#eei ( ! hydroxide-ion 9 ! solution ba?+ x4 ,! addition ( a /rong acid1 l sulphuric acid1 to ?is solution1 by suppress+ ! hydroxide-ion1 small z its conc5tration is1 %\ld increase ! pot5tial ( ! p#bha electrode & ! total pot5tial ( ! cell4 ,?is1 9 fact1 is ! case 7exp472 ! cell work+ "u ^! conditions %[s u ! l>ge/ pot5tial yet obs]v$4#efj ,illu/ration3 ,,fig4 #ad4 ,! arrangem5t ( ! app>atus & ! c\rse ( ! curr5t are %[n 9 ,fig4 #ad4 ,! glass tube ( ! hydrog5 electrode is connect$ ) a hydrog5 g5]ator1 ! tube ( ! oxyg5 electrode ) a cyl9d] or gasomet] fill$ ) oxyg54 ,! hydrog5 electrode is connect$ ) ! negative po/ ( ! voltmet]1 ! oxyg5 electrode ) ! positive po/4 ,s9ce ! hydrog5 ionizes1 "u ! conditions us$1 m rapidly ?an x is =m$ f ! small conc5tration ( ! hydrog5 ions surr\nd+ ! hydrog5 electrode1 hydrog5 ions pass f ! electrode into solution ,a1 leav+ a negative *>ge on ! electrode2 !re is a migration ( sodium ions ?r\gh ! salt bridge 7see p4 #bed7 to solution ,b1 & ! hydrog5 ions =m$ comb9e ) hydroxide ions & produce wat]4 ,9 a simil> way1 oxyg5 passes into solution ,b 9 ! =m ( hydroxide ions & ^! comb9e ) hydrog5 ions ( ! sulphuric acid1 =m+ wat]2 ,,s#db ions migrate f ! solution ,b ?r\gh ! salt bridge t[>d solution ,a & ?us prev5t pol>ization 7p4 #bed74 ,:ile wat] is an actual product ( ! action ( ! cell1 work+ "u ^! conditions1 ! ess5tial feature ( ! oxidation ( hydrog5 is its ionization--,h#b #b ,h2 x w\ld be 9 ! same condition ( oxidation if ! hydrog5 ions comb9$ ) any negative ions o!r ?an ,,ho1 or if !y rema9$ ions 7z !y w\ld1 if sodium *loride surr\nd$ ! hydrog5 electrode74 ,simil>ly1 ! ess5tial feature ( ! r$uction ( oxyg5 is its ionization 9 ! =m ( ,,ho ions2 9 ! pres5t p#bhb in/ance1 ^! actually comb9e ) hydrog5 ions & =m wat]1 b ! r$uction ( oxyg5 w\ld also be accompli%$1 if ! hydroxide ions rema9$ ioniz$ 7z !y w\ld1 if sodium *loride ba!d ! oxyg5 electrode74 ,! =mation ( wat] is ! result ( a union ( ions1 foll[+ ! oxidation-r$uction reaction1 :i* may be express$ 9 ! foll[+ cond5s$ =m3 #b ,h#b #d ,h #b ,,hoh ,o#b #d ,,ho #d ,,ho #d ,h#b,o ,summ>y4--,we ?us f9d t ! oxidation ( hydrog5 by oxyg5 may be us$ to develop an electric curr5t1 exactly 9 ! same way z ! o!r oxidation & r$uction reactions1 :i* we h discuss$1 are f\nd available = ! same purpose4 ,& at a giv5 temp]ature1 ! oxidation is subject to ! influ5ce ( analog\s factors1--! solution-t5sion con/ants1 ! conc5trations ( ! correspond+ ions 9 ! solutions surr\nd+ ! electrodes1 & ! conc5trations ( ! gases4 ,int]pretation ( ,oxidation-,r$uction ,reactions 9 ,t]ms ( ! ,oxyg5-,hydrog5 ,gas ,cell4--,x is possible to int]pret all classes ( rev]sible oxidations & r$uctions1 c>ri$ out 9 aque\s solutions1 9 t]ms ( ?is s-call$ oxyg5-hydrog5 gas cell1 if ! assumption is made t ea* oxidiz+ ag5t1 su* z nitric acid1 p]manganate1 di*romate1 etc41 has a t5d5cy to lib]ate1 ei!r f its own molecules or by its action on wat]1 oxyg5 ( a def9ite conc5tration or pressure1 & t ea* r$uc+ ag5t1 9 turn1 has a t5d5cy to lib]ate hydrog51 f wat]1 ( a def9ite pressure or conc5tration4 ,! pot5tial ( ! oxyg5-hydrog5 cell is dep5d5t on ! conc5trations ( ! gases ) :i* ! electrodes are 9 contact3#efa !re=e1 ea* oxidation & r$uc+ ag5t1 yield+ its own *>act]i/ic conc5tration ( oxyg5 or hydrog51 respectively1 w\ld h a *>act]i/ic con/ant1 correspond+ to ! solution-t5sion con/ants ( ! elem5ts & measur+ its oxidiz+ or r$uc+ p[]4 ,?is int]pretation ( oxidation-r$uction reactions has receiv$ ext5d$ att5tion & recognition4 ,! /udy1 j made1 ( ! oxidation ( hydrog5 by oxyg51 suffici5tly sugge/s ! treatm5t ( oxidation & r$uction f ?is viewpo9t4 ,int]pretation ( ,oxidation-,r$uction ,reactions 9 ,t]ms ( ,direct ,transf]s ( ,electric ,*>ges4--,9 ! /udy ( ! p#bhc oxidation ( z9c by cupric-ion1 ,zn ,cu#b ,cu ,zn#b1 ( ! oxidation ( iodides & sulphides by f]ric salts1 #b ,fe#c #b ,i #b ,fe#b ,i#b1 & #b ,fe#c ,s#b #b ,fe#b ,s1 & ( simil> actions1 x has be5 possible to repres5t ! oxidation-r$uction actions z ! result ( direct transf]s ( electric *>ges betwe5 atoms & _! ions4#efb ,9 ! foll[+ discussions1 ! attempt w be made to int]pret1 9 ! same t]ms1 ! oxidiz+ p[] ( ! mo/ important rema9+ oxidiz+ ag5ts1 :i* include su* comp\nds z nitric1 p]manganic1 *romic1 ars5ic & simil> oxyg5 acids4 ,! int]pretation w avoid ! assumption ( ! lib]ation ( oxyg5 & hydrog51 "u hypo!tical1#efc &1 sometimes1 enorm\s pressures1 z int]m$iate products 9 ! actions4 ,ars5ic ,acid z an ,oxidiz+ ,ag5t4--,ars5ic acid is occasionally us$ z an oxidiz+ ag5t 7e4g4 9 ! anil9e-dye indu/ry71 &1 al?\gh x is n a v p[]ful "o1 its /udy is ( !oretical int]e/4 ,if to a solution ( potassium ars5iate "s potassium iodide is add$1 practically no iod9e is lib]at$ 7exp474 ,if dilute hydro*loric acid1 9 excess1 is add$ to ?is mixture1 iod9e is sl[ly lib]at$ 7exp474 ,b ! addition ( conc5trat$ hydro*loric acid causes iod9e to be lib]at$ at once 9 v l>ge am\nts 7exp474 ,we may ask 9 :at way ! p#bhd addition ( ! conc5trat$ acid causes su* a decid$ diff]5ce 9 ! ease & spe$ ) :i* ars5ic acid oxidizes ! iodide-ion to free iod9e & is r$uc$1 9 turn1 to ars5i\s acid & its d]ivatives4#efd ,we may recall ! fact t a solution ( potassium ars5iate1 to :i* dilute hydro*loric acid has be5 add$1 w rema9 cle> = "s "t :5 ! mixture is saturat$ ) hydrog5 sulphide 7exp474 ,if a consid]able excess ( conc5trat$ hydro*loric acid is add$ to ?is mixture1 hydrog5 sulphide imm$iately =ms a d5se precipitate 7exp47 ( ars5ic p5tasulphide--presumably ?r\gh ! union ( qu9quival5t ars5ic-ion ) ! sulphide-ion3 #b ,z#e #e ,s#b ,z#b,s#e 7see p4 #bdg74 ,?is behavior sugge/$ t ars5ic acid1 al?\gh a mod]ately /rong acid1 might nev]!less be some:at amphot]ic1 might h slight basic prop]ties1 z well z its ord9>y acid functions4 ,! relation is express$ 9 ! equations3#efe #c ,h ,as,o#dc 7,,ho7#c;,as,o 7,,ho7#c;,as,o ,,hoh ,z7,,oh7#e ,z#e #e ,,ho4 ,s9ce oxidations by ars5ic acid involve its r$uction to ars5i\s acid1 conta9+ trival5t1#eff 9 place ( qu9quival5t ars5ic1 "o might well suspect1 t ! oxidiz+ compon5t is ! qu9quival5t ars5ic-ion1 ,z#e1 ! dis*>ge ( two ( ^: positive *>ges w\ld cause oxidation 7e4g4 ( iodide-ion71 exactly z ! dis*>ge ( positive *>ges at ! positive pole ( an electric curr5t causes oxidation 7p4 #beb73 ,z#e #b ,i ,z#c ,i#b4 p#bhe ,9 a solution ( potassium ars5iate1 we w\ld h only ! fa9te/ trace ( ! ion ,z#e1 s9ce ! addition ( an alkali to ! sy/em1 express$ 9 ! above equations1 w\ld c>ry ! rev]sible reactions t[>ds ! left4 ,! addition ( dilute hydro*loric acid to ! sy/em mu/ c>ry ! reactions t[>ds ! "r & increase ! conc5tration ( ,z#e2 ! addition ( conc5trat$ acid mu/ increase ! conc5tration ( ,z#e v mu* m4 ,ev5 if ! conc5tration ( ,z#e rema9$ m9ute1 ! oxidiz+ p[] w\ld be increas$ proportionally to ! ratio ( ! conc5trations 9 ! fir/ & ! la/ solutions4 ,a millionfold increase 9 conc5tration1 ev5 :5 we are deal+ ) v small numb]s1 w\ld imply a millionfold increase 9 ! activity ( ! solution4 ,if1 !n1 ! oxidiz+ compon5t ( ars5ic acid is ! qu9quival5t ion1 ,z#e1 :i* w\ld t5d to dis*>ge two ( its positive 7oxidiz+7 *>ges1 ars5ic acid %\ld be a mu* m p[]ful oxidiz+ ag5t 9 /rong acid solution ?an 9 alkal9e or neutral solutions4 ,we ?us arrive at ! conclusion t ! addition ( hydro*loric acid to a mixture ( ars5iate & iodide may be effective1 9 br++ ab\t ! r$uction ( ! ars5iate & ! oxidation ( ! iodide1 prim>ily because ( its action on ars5ic acid1 p]haps by facilitat+ its ionization z a base1 & t x is n effective ?r\gh any action on ! iodide1 = in/ance by produc+ free hydroiodic acid1 z is (t5 assum$4 ,?is conclusion may easily be te/$ ) ! aid ( ! *emomet] 7see p4 #bec73 potassium ars5iate aga9/ potassium iodide gives only ! fa9te/ possible curr5t1 b>ely p]ceptible ) ! aid ( a v s5sitive voltmet]4#efg ,! addition ( hydro*loric acid to ! beak] conta9+ ! potassium iodide does n increase ! pot5tial 7x r decreases x some:at71 :]eas ! addition ( ! conc5trat$ acid to ! potassium ars5iate solution produces a mo/ decid$ increase 9 ! pot5tial#efh 7exp474 ,x is evid5t1 !re=e1 t ! addition ( ! acid is prim>ily & directly int5d$ to increase ! oxidiz+ p[] ( ! ars5ic acid1 r ?an to increase ! r$uc+ p[] ( ! iodide4 p#bhf ,! m common me?ods ( express+ oxidation-r$uction reactions ( ?is type are illu/rat$ 9 ! foll[+ equations3 ,na#c;,as,o#d #b ,,hi ,na#c;,as,o#c ,h#b,o ,i#b 7#a7efi & ,as,o#dc #b ,h #b ,i ,as,o#cc ,h#b,o ,i#b4 7#b7 ,bo? ( ^! =ms ( expression give ! net results ( ! action correctly4 ,nei!r attempts to int]pret ! int]e/+ & important fact t ! r$uction ( ars5ic acid is facilitat$ by ! pres5ce ( acids 7( hydrog5-ion74 ,x is1 at lea/1 also p]missible to consid] ,z#e ions to be pres5t & to express ! oxidation-r$uction reaction ) ! aid ( ?is conception1#egj z has be5 done 9 ! previ\s discussion4 ,9 ! f9al analysis1 ?is me?od seems to h ! advantage ( %[+ directly ! *anges ( ! val5ces#ega 7electric *>ges7 ( ! atoms involv$ 9 ! oxidation-r$uction1 & x also expresses1 cle>ly & def9itely1 ! relation ( ! hydrog5-ion to ! action4#ega ,! foll[+ case furni%es an illu/ration z to h[ ! new po9t ( view works out f ! /&po9t ( a quantitative /udy ( an oxidation-r$uction reaction ( ?is type#egb3 uranyl salts1 su* z ! sulphate ,,uo#b,,s#d1 are oxidiz+ reag5ts1 :i* are readily r$uc$1 p>ticul>ly 9 acid solutions1 to uran\s salts 7e4g4 to ! sulphate1 ,u7,,s#d7b74 ,! pot5tial ( a mixture ( uranyl & uran\s salts is f\nd#egc to dep5d on ! action express$ 9 ! equation ,,uo#bb #d ,h #b ,u#d #b ,h#b,o4 ,= ! condition ( equilibrium 7z]o pot5tial71 x foll[s t ,,uo#bb ,h#d _/ ,u#d ,kequil4 7#c7 ,! value ( ?is con/ant1 at #ah1 is f\nd1 by calculation1#egd to be approximately #a _/ #ajbd4 ,n[1 ! uranyl-ion ,,uo#bb may be assum$ to h ! p[] ( ioniz+1 ) ! aid ( wat]1 to a v slight degree into ions ,u#f & ,,ho1 accord+ to ,,uo#bb #b ,h#b,o ,u7,,oh7#db ,u#f #d ,,ho4 7#d7 ,= ! ionization ( an extremely weak base ( ?is "*1 we h1 fur!r1 ,u#f ,,ho-#d _/ ,,uo#bb kbase4 ,&1 s9ce ,,ho ,k,,hoh _/ ,h1 we also f9d1 by sub/itution & by solv+ = ,u#f1 ,u#f ,,uo#bb ,h#d kbase _/ 7,k,,hoh7#d4 7#e7 p#bhg ,9 o!r words1 we may sub/itute ,u#f & a con/ant factor ,k,,hoh#d _/ kbase = ,,uo#bb ,h#d 9 ! fir/ t]m 7num]ator7 ( ! oxidation-r$uction equation 7#c71 d]iv$ f ,lu!r's quantitative "w4 ,we ?us obta93 ,u#f _/ ,u#d ,kequil4 kbase _/ ,k,,hoh#d ,k1 7#f7 :i* mu/ agree j z well ) ! quantitative data1#ege z does ! orig9al equilibrium equation 7#c74 ,x foll[s1 t we may write ! *emical equation1 = ! action 9 acid solutions1 simply ,u#f ,u#d1 exactly z we h ,fe#c ,fe#b 7p4 #bfi74 ,u#f _c be measur$1 z yet1 b 9 ! analog\s case ( ,fe#c ,fe#b1 :]e bo? t]ms ( ! equilibrium equation are accessible to direct measurem5t1 ! exp]im5tal evid5ce di/9ctly favors#egf ! views express$4#egg ,p]manganic ,acid1 ,*romic ,acids1 etc41 z ,oxidiz+ ,ag5ts4--,we may ext5d ! same views to ! oxidiz+ p[] ( su* important ag5ts z p]manganic1 di*romic1 & nitric acids4 ,9 ea* case we may assume t ! oxidiz+ compon5t is a highly *>g$ positive ion1 e4g4 9 ! case ( ,k,mn,o#d a septaval5t manganese-ion1 ,mn#g1 ^: oxidiz+ p[] w dep5d on its t5d5cy to dis*>ge "p ( its heavy positive electrical *>ge & ^: effici5cy1 9 accordance ) ! law ( equilibrium1 w also be proportional to ! conc5tration1 9 :i* ! highly *>g$ ion is pres5t4 ,p]manganate is us$ z a favorite oxidiz+ ag5t 9 ! laboratory1 = in/ance1 9 ! oxidation ( f]r\s to f]ric salts 9 quantitative analysis2 ! action proce$s quantitatively & rapidly 9 acid solution1 & ! end ( ! action is recogniz$ by ! fact t ! int5se p9k color ( ! p]manganate is n de/roy$ 7exp474 p#bhh ,if we br+ p]manganate1 aga9/ potassium iodide1 into ! beak]s ( ! *emomet] 7p4 #bec71 we f9d t x is a mu* m vigor\s oxidiz+ ag5t ?an is ars5ic acid1 & aga9 we f9d t ! addition ( acid 7sulphuric7 to ! p]manganate solution enorm\sly increases ! pot5tial 7exp47 & !re=e its oxidiz+ p[]4 ,! addition ( an acid w\ld1 obvi\sly1 enorm\sly increase ! conc5tration ( a positive septaval5t ion1 if p]manganic acid is assum$ to be1 to a slight ext5t1 base =m+ & !re=e amphot]ic3 ,h ,mn,o#d 7,,ho7,mn,o#c 7,,ho7,mn,o#c #c ,,hoh ,mn7,,oh7#g ,mn#g #g ,,oh4 ,simil> exp]im5ts may be made ) f]r\s sulphate aga9/ p]manganate4 ,! oxidation ( f]ro-ion1 or ( iodide-ion1 may be repres5t$1 mo/ simply1 by ! equations3 #b ,mn#g #aj ,fe#b #b ,mn#b #aj ,fe#c & #b ,mn#g #aj ,i #b ,mn#b #e ,i#b4 ,ea* heptaval5t manganese ion is d]iv$ f a salt1 su* z ,mn,x#g or ,mn#b,y#g1 &1 consequ5tly1 :5 two manganese ions ,mn#g are r$uc$1 t5 unival5t negative ions ,x1 or five bival5t ions ,y1 are lib]at$ & become available = salt =mation ) ! f]ric ions1 produc$1 or ) ! hydrog5 ions 7f hydroiodic acid7 set free by ! oxidation ( ! iodide ions to iod9e4 ,?us1 ! oxidation ( f]r\s sulphate by p]manganate1 9 ! pres5ce ( sulphuric acid1 may be repres5t$1 9 great] detail1 by ! equations3 #b ,k,mn,o#d ,h#b,,s#d ,k#b,,s#d #b ,h,mn,o#d 7#a7 #b ,h,mn,o#d #g ,h#b,,s#d ,mn#b7,,s#d7g #h ,h#b,o 7#b7 ,mn#b7,,s#d7g #b ,mn#g #g ,,s#db 7#c7 #b ,mn#g #g ,,s#db #aj ,fe#b #aj ,,s#db #b ,mn#b #a ,o,fe#c #ag ,,s#db 7#d7 #b ,mn,s,o#d #e ,fe#b7,,s#d7c 7#e7 ,analog\s results are obta9$ ) potassium *romate or di*romate aga9/ potassium iodide1 f]r\s sulphate1 hydrog5 sulphide1 & o!r r$uc+ ag5ts4 ,nitric ,acid4--,x is *>act]i/ic ( nitric acid t1 ioniz$ z an acid1 x is n a p[]ful oxidiz+ ag5t2 t is1 ! nitrate-ion1 ,,no#c1 is n ! oxidiz+ compon5t4 ,= in/ance1 a nitrate1 su* z potassium nitrate1 9 aque\s solution1 does n appreciably oxidize f]ro-ion or iodide-ion 7exp474 ,conc5trat$ nitric acid1 or a mixture ( a l>ge excess ( conc5trat$ p#bhi sulphuric acid ) a nitrate1 are f> m effective 9 oxidiz+ ! sub/ances m5tion$1 z %[n by exp]im5ts ) ! *emomet] & ) ! mixtures describ$4 ,x is significant t1 9 conc5trat$ nitric acid1 & 9 ! pres5ce ( conc5trat$ sulphuric acid1 ! basic ionization ( nitric acid ,h ,,no#c 7,,ho7,,no#b 7,,ho7,,no#b #b ,,hoh ,n7,,oh7#e ,n#e #e ,,ho w\ld be facilitat$ by ! high conc5tration ( hydrog5-ion4 ,summ>y4--,9 e in/ance1 !n1 we f9d t x is possible to produce an electric curr5t by us+ "o ( ^! common1 p[]ful oxidiz+ ag5ts 9 aque\s solution1 j z x is possible ) oxyg5 & ) ! simpl] ag5ts discuss$ e>li]4 ,:atev] ! !ory ( ! =mation ( ! curr5t1 :e!r we are deal+1 9 ! la/ cases consid]$1 ) acids :i* h ! capacity to ionize m9imally z bases1 =m+ highly *>g$ positive ions1 ^: dis*>ge involves an oxidation ( ! sub/ance receiv+ ! dis*>g$ electricity1 or :e!r we accept ! view t oxyg5 is lib]at$ by !m 9 exce$+ly conc5trat$ =m & t5ds to =m 9 aque\s solutions ! hydroxide-ion1 ,,ho1 unque/ionably ! close/ possible relation has be5 e/abli%$ betwe5 oxidation-r$uction reactions & electrical relations1 z =mulat$ on ! basis ( ! !ory ( ionization4 ,9 all cases1 at a con/ant temp]ature1 z dem&$ by ! law ( mass action1 ! net result ( an action w dep5d on con/ant factors1 measur+ ! t5d5cies ( atoms to assume or lose electric *>ges 7electrons71 & on v>iable factors1 ! conc5trations ( ! react+ compon5ts4 ,oxidation ( ,organic ,comp\nds4--,9 conclusion1 x may be ask$ :e!r ! oxidation ( organic comp\nds may also be br\ght into relation ) electrical *>ges & int]pret$ on ! basis ( ! !ory :i* has be5 pres5t$4 ,= ?is purpose we may /udy ! oxidation ( "o ( ! simple/ ( organic comp\nds1 =maldehyde ,,*#b,o1 :i* =ms ! active compon5t 9 solutions ( =mal94 ,=maldehyde is also intimately relat$ to "s ( ! mo/ important food products1 ! c>bohydrates1 ^: oxidation is utiliz$ 9 ! animal economy4 ,x is =m$#egh 9 ! gre5 leaves ( plants by ! p#bij r$uction ( c>bon dioxide1 absorb$ f ! atmosph]e1 ) ! aid ( ! en]gy ( ! sun's light3 ,,co#b ,h#b,o ,,*#b,o ,o#b4 ,x is readily cond5s$1 =m+ glucose 7#f ,,*#b,o ,c#f;,h#ab,o#f71 cane sug> ,c#ab;,h#bb,o#aa1 & /ill m complex c>bohydrates1 su* z />*4 ,=maldehyde1 l o!r aldehydes1 is readily oxidiz$4 ,a favorite reag5t1 us$ 9 oxidiz+ x1 is an ammoniacal solution ( silv] nitrate 7exp471 ! sep>ation ( silv] f su* a solution be+ a *>act]i/ic reaction ( aldehydes4 ,! reag5t is r5d]$ /ill m s5sitive by ! addition ( sodium or potassium hydroxide4#egi ,we may ask h[ we w\ld int]pret1 f ! po9t ( view ( ! electric !ory ( oxidation & r$uction1 ! oxidation ( =maldehyde & ! r$uction ( silv] nitrate to silv]1 "u ^! conditions4 ,accord+ to ! !ory1 ! oxidiz+ ag5t 9 silv] nitrate is ! silv]-ion1 ! dis*>ge ( :i* gives positive electricity1 :i* ! oxidiz$ sub/ance1 ! =maldehyde1 mu/ absorb4 ,b 9 a silv] nitrate solution !re is a f> l>g] conc5tration ( ! silv]-ion ?an 9 an ammoniacal solution 7p4 #bbj71 conta9+ ! same total conc5tration ( silv]4 ,! complex silv]-ammonium-ion ,ag7,,nh#c7b1 x may be recall$1 is a r /able "o1#ehj &1 consequ5tly1 ! addition ( ammonia to silv] nitrate %\ld decid$ly weak5 its oxidiz+ p[]4 ,/ill1 ! practical use ( ammonia1 especially 9 comb9ation ) sodium hydroxide1 is f\nd to be mo/ effective4 ,we are l$ to suspect t1 9 spite ( ! unt[>d effect ( ammonia on ! oxidiz+ p[] ( ! silv] comp\nd1 an alkal9e solution is desirable = ! sake ( ! effect ( ! alkali on =maldehyde1 ! r$uc+ sub/ance involv$4 ,to foll[ up ?is conclusion1 we mu/ next consid]1 9 "s detail1 ! nature ( =maldehyde2 we %all pres5tly f9d t ! conclusion1 :i* we h j rea*$1 z to ! probably favorable effect ( alkali on ! r$uc+ p[] ( =maldehyde1 w be v]ifi$ by exp]im5ts1 :i* ! consid]ation ( =maldehyde w sugge/4 ,! oxidation ( =maldehyde may mo/ cle>ly be =mulat$ on ! basis ( views1 develop$ by ,nef1 on ! =mation ( me?yl5e#eha d]ivatives1 conta9+ bival5t c>bon atoms4 ,a solution p#bia ( =mal9 conta9s =maldehyde 9 a v>iety ( =ms1 9 a v complex condition ( equilibrium4 ,( ^! comp\nds1 ! aldehyde1 ,,*#b,o1 probably exi/s 9 two =ms1 :i* h ! same composition & molecul> weight1 b :i* diff] 9 ! arrangem5t ( ! atoms 9 ! molecules 79 ! /ructure ( ! molecules72 we probably h ,,*#b,o ,,*7,,oh71 ! =m] ( :i* 7,,*#b,o7 is1 mo/ likely1 by f> ! m /able & ! *ief "o ( ^! two sub/ances1 pres5t "u ord9>y conditions4 ,! second comp\nd ,,*7,,oh7 may be pres5t 9 traces only4 ,"o diff]5ce1 we note1 lies 9 ! position ( "o ( ! hydrog5 atoms 9 ! respective molecules2 ! second =m conta9s a hydroxide gr\p 7,,oh71 :i* gives x ! prop]ties ( an acid & r5d]s x capable ( =m+ salts ,,*7,o,me7 ) bases4 ,b ! molecule ( ?is second =m also w\ld conta9 a c>bon atom1 only two ( ^: val5ces are satisfi$ 7by ,h & ,,oh71 two ( ! ord9>y f\r val5ces ( a c>bon atom be+ ?us left free or unsaturat$4 ,we may indicate ! two free c>bon val5ces 9 ! =mula ,,*7,,oh74 ,su* an unsaturat$1 bival5t c>bon atom ,c w\ld be p>ticul>ly s5sitive to oxidation4#ehb ,besides ^! two =ms1 a =mal9 solution also conta9s a polym]iz$ =m1 probably 7,,*#b,o7#b1 :i* 9 dilute solution1 or "u ! influ5ce ( heat1 sl[ly breaks d[n into =maldehyde1 7,,*#b,o7#b #b ,,*#b,o4 ,! addition ( alkali to ! mixture probably leads to ! =mation ( ! salt ,,*7,o,me71 ?us di/urb+ all ! conditions ( equilibrium & lead+ to ! trans=mation ( a v mu* l>g] "p ( ! aldehyde into a comp\nd conta9+ ! *>act]i/ic unsaturat$ 7bival5t7 c>bon1 ?an 0 orig9ally pres5t4 ,! aldehyde w ?us become m susceptible to oxidation z a result ( ! enorm\s increase 9 ! conc5tration ( ! oxidizable compon5t4 ,we may assume ?is to be ei!r ! salt1 ,,*7,o,me71 or its negative ion1 ,,*7,o71 or bo?1 or "s analog\s d]ivative4 ,fur!r1 ! two free val5ces ( a bival5t c>bon atom may be consid]$ to consi/ ( a positive & a negative *>ge ( electricity1 ei!r actual or pot5tial1#ehc & ! oxidation w consi/ p#bib prim>ily 9 ! absorption ( two positive *>ges1 f ! oxidiz+ ag5t1 to conv]t ! negative *>ge on ! c>bon atom1 say 9 ,,*7,o,na71 into a positive *>ge4#ehd ,if ! oxidiz+ ag5t is alkal9e silv] nitrate solution1 we may =mulate ! successive actions z foll[s3 7,na,o7,,hc #b ,ag 7,na,o7,,hc#b #b ,ag 4 ,! two positive silv] ions correspond to two negative ions1 e4g4 hydroxide ions ,,ho1 :i* are set free by ! dis*>ge ( ! silv] ions1 & :i*1 9 turn1 w comb9e ) ! oxidiz$ c>bon atom hold+ ! two positive *>ges3 7,na,o7,,hc#b #b ,,ho 7,na,o7,,hc7,,oh7#b 7,na,o7,,hc3,o ,h#b,o4 ,! salt =m$1 ,,hco#b,na1 is sodium =mate1 :i* is ! fir/ isolat$ product ( ! oxidation ( =maldehyde4 ,x w\ld appe>1 f ?is po9t ( view1 t ! alkal9e nature ( ! silv] nitrate mixture is advantage\s prim>ily because a base is requir$ by ! =maldehyde1 ! r$uc+ ag5t1 to conv]t x into "s readily oxidizable =m4 ,& ! prov$ effici5cy ( ! alkal9e mixture 7see above7 makes x appe> probable t ! advantage ga9$ by ?is result m ?an (fsets ! loss 9 oxidiz+ p[]1 suff]$ by ! silv] nitrate foll[+ ! suppression ( its real oxidiz+ compon5t1 ! silv]-ion1 :51 9 ! pres5ce ( ammonia1 ! latt] is conv]t$ l>gely into ! ion1 ,ag7,,nh#c7b4 ,ammonia1 9 turn1 is employ$ 9 ! oxidiz+ mixture1 ess5tially ) ! object ( prev5t+ ! precipitation ( ! silv]-ion1 z silv] oxide1 by ! hydroxide-ion ( an alkal9e mixture4 ,^! conclusions1 z well z1 9 p>ticul>1 ! ma9 conception t 9 ! oxidation ( =maldehyde !re is an actual transf] ( electrical *>ges1 may be fully confirm$ ) ! aid ( ! *emomet]4#ehe ,,exp4 ,a small beak]1 conta9+ a plat9um electrode1 :i* is connect$ ) ! positive po/ ( ! voltmet]1 is half fill$ ) a solution ( silv] & sodium nitrates4 ,a simil> small beak]1 conta9+ a plat9um electrode lead+ to ! negative po/ ( ! voltmet]1 is *>g$ ) a solution ( sodium nitrate 7to r5d] ! solution a good conductor7 & ) "s =mal94 ,! solutions 9 ! two beak]s are connect$ by means ( a salt-bridge conta9+ sodium nitrate4 p#bic ,only a v slight curr5t is produc$ "u ^! conditions2 ! pot5tial betwe5 silv] nitrate & =maldehyde is f\nd to be extremely small4 ,if1 n[1 sodium hydroxide is add$ to ! =mal9 mixture1 an enorm\s increase 9 pot5tial is obs]v$1 prov+1 unmi/akably1 t ! addition ( ! alkali to ! =mal9 solution enorm\sly increases ! conc5tration ( ! react+1 oxidizable compon5t4#ehf ,:5 "s ammonia is add$ to ! silv] nitrate mixture1 we f9d1 z anticipat$1 t ! oxidiz+ p[] ( ! silv] solution is greatly r$uc$1 ! silv]-ion be+ conv]t$ into ! complex ion1 ,ag7,,nh#c7b2 b ! pot5tial is /ill v mu* great] ?an ! pot5tial betwe5 silv] nitrate & =mal9 )\t any alkali--:i* %[s t ! advantage ( us+ alkali ) ! =maldehyde greatly outweighs ! disadvantage ( us+ ammonia ) ! silv] nitrate4 ,an electric curr5t may also be readily obta9$ by comb9+ alkal9e =maldehyde ) o!r oxidiz+ ag5ts--= in/ance ) an oxyg5 electrode 7p4 #bgi74 ,we f9d 7exp47 t ! oxidation proce$s ) rem>kable ease "u ^! conditions4 ,p]manganate1 di*romate1 etc41 may be sub/itut$ = oxyg51 ) ! same g5]al result4 ,summ>y4--,x is cle>1 !n1 t ! oxidation ( an organic sub/ance may readily be int]pret$ z consi/+1 ultimately1 9 a transf] ( electrical *>ges1 ( exactly ! same nature1 z is f\nd 9 ! o!r oxidation reactions :i* we h consid]$1 p#bid & t ! conditions = produc+ a maximum curr5t1 z inve/igat$ ) ! aid ( ! *emomet]1 give u1 aga91 important guidance 9 foll[+ ! c\rse ( ! reactions4 ,x is ne$less to say t ! oxidation ( o!r organic comp\nds1 su* z glucose1 alcohol1 etc41 may be pr(itably /udi$ f ! same po9t ( view4 ,x also foll[s1 f ! conclusions rea*$1 t1 "u prop] exp]im5tal conditions1 electricity1 9 ! =m ( a curr5t1 mu/ be capable ( effect+ ! oxidation1 or ! r$uction1 ( organic z well z inorganic comp\nds 7p4 #beb74 ,ext5d$ inve/igations h1 inde$1 %[n t electric curr5ts belong to ! mo/ important & effici5t ag5ts = ?is purpose1 because ! oxidation1 or ! r$uction1 ( ! organic comp\nd becomes susceptible to ! mo/ exact control ?r\gh ! regulation ( ! pot5tials us$4#ehg ,tables & ,summ>ies4--,9 ! fir/ table ! equilibrium 7solution-t5sion7 con/ants ( a numb] ( metals & non-metallic elem5ts are giv54 ,! table is foll[$ by brief explanations ( its mean+ & a summ>y ( "s ( its m important applications4 ,,table,a ,,( ,,equilibrium 7,,solution-,,t5sion7 ,,con/ants 7,,9 ,,mol> ,,t]ms7 ,,& ,,( ,,pot5tial ,,diff]5ces ,,betwe5 ,,elem5ts ,,& ,,_! ,,ions ,,9 ,,unimol> ,,aque\s ,,solutions4 ,elem5t1 ,ion4 ,e4,p4,el41,ion4 ,k,ion4 ,k1 ,k,b 7#b4ib7 #f;,e#ej ,na1 ,na,c #b4dd #b4e;,e#db ,ba1 ,ba#b 7#b4ed7 #b4a;,e#hh ,sr1 ,sr#b 7#b4di7 #d4j;,e#hf ,ca1 ,ca#b 7#b4bh7 #b4j;,e#gi ,mg1 ,mg#b 7#b4bf7 #d4a;,e#gh ,al1 ,al#c;,d #j4iii 8 #a4c;,e#eb ,mn1 ,mn#b #j4gih #e4g;,e#bg ,zn1 ,zn#b #j4dic #a4d;,e#ag ,cd1 ,cd#b #j4adc #i4e;,e#d ,fe1 ,fe#b;,e #j4abb 8 #a4h;,e#d ,co1 ,co#b;,f #j4jach 8 #j4ccad ,ni1 ,ni#b;,g #j4ajh 8 #a4h;,e#d ,sn1 ,sn#b #j4jhe #a4a;,e#c ,pb1 ,pb#b #j4abi #c4c;,e#e ,h#b1 ,h,h #j4bgg #a4eb;,e#e ,cu1 ,cu#b #j4fjf #h4c;,e#bb ,z1 ,z #j4egj #b4g;,e#cj ,bi1 ,bi#c #j4ffh #a4d;,e#ce ,sb1 ,sb#c #j4gdc #a4g;,e#ci ,hg1 ,hg #a4jbg #a4ch;,e#ah ,ag1 ,ag #a4jdh #f;,e#ai ,pt1 ,pt#d #a4adj #e;,e#hj ,au1 ,au#c #a4cef #a4h;,e#ga ,f#c1 ,f,h 7#b4bd7 #i4j;,e#hh ,cl#b1 ,cl,h #a4fid #c4af;,e#bi ,br#b1 ,br #a4bgj #a4bc;,e#bb ,i#b1 ,i #j4gig 8 #g4bf;,e#ac ,o#b1 ,,ho,i #j4fih #a4cf;,e#ab ,,table ,,notes3 ,a4 ,! table is bas$ on ,wilsmore's compilation ( solution-t5sion pot5tials1 ,z4 phys4 ,*em41 #cf1 #ia 7#aija74 ,b4 ,values 9 p>5!ses h be5 e/imat$ by indirect measurem5ts4 ,c4 ,g4 ,n4 ,lewis1 ,j4 ,am4 ,*em4 ,soc41 #cb1 #adfg 7#aiaj74 ,d4 ,values m>k$ )8 are unc]ta94 ,e4 ,calculat$ f ! data ( ,ri*>ds & ,behr 7,z4 phys4 ,*em41 #eh1 #cja 7#aijg771 :o f\nd ! pot5tial ( iron aga9/ #j4e mol> ,fe,s,o#d to be #j4ae volt4 ,! degree ( ionization ( #j4e mol> ,fe,s,o#d is tak5 z #bb4 #be4h 7,kohlraus* & ,holborn1 loc4 cit41 p4 #aeb7 & is tak5 z #aag1 z = ,zn,s,o#d 7ibid41 p4 #bjj74 ,on acc\nt ( ! d\btful value = ! degree ( ionization1 ! values 9 ! table are m>k$81 b ! value f\nd by ,ri*>ds & ,behr appe>s to be q accurate4 ,f4 ,calculat$ f ! data ( ,s*ildba* 7,z4 fr ,elektro*41 #af1 #ifg 7#aiaj774 ,! same unc]ta9ty z to ! degree ( ionization exi/s z t discuss$ 9 ! previ\s footnote4 ,g4 ,calculat$ f ! data ( ,e4 ,p4 ,s*o* 7,am4 ,*em4 ,j41 #da1 #bjh 7#aiji774 ,! same unc]ta9ty z to ! degree ( ionization exi/s z t discuss$ 9 footnote #e1 p4 #bid4 ,h4 ,! values = gase\s elem5ts ref] to ! gases "u "o atmosph]e pressure4 ,i4 ,! pot5tial ( oxyg5 at #ah1 #gfj mm41 aga9/ an alkal9e solution 9 :i* ,,ho #a4 ,k,ion ref]s to ! conc5tration ( ,,ho1 ) :i* oxyg5 "u atmosph]ic pressure w\ld be directly 9 equilibrium1 at #ah4 ,! pot5tial diff]5ces1 giv5 9 ! table1 are bas$ on ! assumption t ! absolute z]o ( pot5tial is at su* a po9t1 t ! s-call$ /&>d normal calomel electrode has a value ( #j4ef volt relative to ?is z]o 7cf4 ,o/wald1 ,z4 phys4 ,*em41 #cf1 #ig 7#aija774 ,! exact det]m9ation ( ?is value is a v difficult matt]4 ,rec5tly ,palma] 7ibid41 #ei1 #abi 7#aijg771 locat$ ! absolute z]o at a po9t #j4jd volt m positive ?an ! above1 mak+ ! absolute pot5tial ( ! normal calomel electrode1 approximately1 #j4eb volt4 ,to ref] pot5tials1 giv5 9 ?is book1 to ?is new z]o1 "o w\ld subtract #j4jd volt f all positive pot5tials & add #j4jd to ! numb]s repres5t+ negative pot5tials 7e4g4 ,e4 ,p4,zn1,zn#b w\ld become #j4efi 9 place ( #j4ebi volt74 ,s9ce ! equilibrium 7solution-t5sion7 con/ants are calculat$ f ! pot5tial diff]5ces ref]r$ to ! absolute z]o 7p4 #bei71 any *ange 9 ! z]o involves correspond+ *anges 9 ! values ( ! equilibrium con/ants1 z calculat$ = ?is book4 ,h[ev]1 x %\ld be not$ t all pot5tial diff]5ces w\ld be correct$ by ! same con/ant quantity 7#j4jd volt = ,palma]'s z]o73 all ! equilibrium con/ants = unival5t metallic ions w\ld be increas$ proportionally to a con/ant factor c 7c is v ne>ly equal to #e1 = ,palma]'s z]o71 ! equilibrium con/ants = bival5t metallic ions w\ld be increas$ proportionally to c#b1 etc4 ,! equilibrium ratio = two metals & _! ions w\ld 9 no wise be *ang$ by ^! alt]ations3 e4g4 = ! equilibrium betwe5 z9c & copp] & p#bif _! ions 7p4 #bfg71 ,kequil4 ,k,zn#b _/ ,k,cu#b2 ! factor c#b w\ld be introduc$ into bo? t]ms ( ! ratio & w\ld n affect ! value ( ! latt]4 ,= ! condition ( equilibrium betwe5 silv] & copp] & _! ions 7p4 #bfg7 ,kequil4 ,k,ag#b _/ ,k,cu#b1 & s9ce 7c7#b c#b1 ?is equilibrium ratio w\ld also n be affect$4 ,= elem5ts1 :i* produce negative ions1 ! correspond+ correction factors w\ld be #a _/ c1 #a _/ c#b1 etc41 & ! equilibrium relations betwe5 two su* elem5ts & _! ions likewise w\ld rema9 un*ang$4 ,s9ce ^! equilibrium relations are ! significant ones 9 ?is "w1 & s9ce our conclusions h be5 bas$ on !m1 x is cle> t a *ange 9 ! absolute z]o w\ld n affect ! conclusions rea*$4 ,on acc\nt ( ! unc]ta9ty atta*+ to ! det]m9ation ( ! absolute z]o ( pot5tial1 x is pref]r$1 9 practice1 to report ! exp]im5tally det]m9$ pot5tials z measur$ aga9/ a con/ant1 well-def9$ electrode 7su* z ! calomel electrode or a hydrog5 electrode7 & ?us to elim9ate ! v>iation1 :i* a *ange 9 ! det]m9ation ( ! z]o pot5tial w\ld make necess>y4 ,h[ev]1 = an elem5t>y discussion ( oxidation-r$uction reactions1 f ! same viewpo9t z is us$ 9 consid]+ all o!r rev]sible *emical actions1 ! idea ( ! absolute pot5tial has c]ta9 advantages1 mak+ a uni=m treatm5t possible4 #a4 ,mean+ ( ,k,ion4 ,"u ,k,ion is giv51 = ea* elem5t1 ! conc5tration ( its ion1 ) :i* ! elem5t w\ld be directly 9 equilibrium at ! ord9>y temp]ature 7see p4 #beh74 ,! con/ants = gase\s elem5ts repres5t ! con/ants ( ! gases "u atmosph]ic pressure4 #b4 ,! ,condition = ,equilibrium betwe5 ,two ,elem5ts & ,_! ,ions4 ,! condition ( equilibrium 9 a sy/em ( two elem5ts & _! ions may be f\nd ) ! aid ( ! con/ants ,k,ion1 z foll[s3 ,= ,zn ,cu#b ,zn#b ,cu we h = ! condition ( equilibrium 7see p4 #bfg7 ,zn#b _/ ,cu#b ,k & ,k ,k,zn#b _/ ,k,cu#b #a4d;,e#ag _/ #h4c;,e#bb #a4g;,e#ch4 ,z9c-ion mu/ be pres5t 9 enorm\s excess 9 ! condition ( equilibrium & z9c w precipitate copp] f solutions ( cupric salts until ?is relation is e/abli%$4 ,! suppression ( ! cupric-ion--by precipitation 9 ! =m ( insoluble salts or by conv]sion into v /able complex ions--makes ,cu#b exce$+ly small & makes x increas+ly difficult = z9c to precipitate copp]1 &1 "u c]ta9 conditions1 ! ord9>y c\rse ( ! action may be rev]s$ 7p4 #bfh74 ,= ,cu #b ,ag ,cu#b #b ,ag 1 we h 7p4 #bfg7 ,cu#b _/ ,ag#b ,k & ,k ,k,cu#b _/ ,k,ag#b #h4c;,e#bb _/ 7#f;,e#ai7b #b4c;,e#ae4 #c4 ,pot5tial ,diff]5ces ,calculat$ ) ! ,aid ( ,k,ion4 ,= metallic elem5ts1 :i* s5d out positive ions1 9 contact ) an aque\s solution conta9+ ! ion 9 conc5tration ,c1 ! pot5tial diff]5ce is 7see p4 #bfa7 ,me1 ,ionv 7#j4jege _/ v7 log7,c _/ ,k,ion7 volts1 p#big & = elem5ts :i* =m negative ions 7see footnote #a1 p4 #bfa71 ,elem41 ,ionv 7#j4jege _/ v7 log7,c _/ ,k,ion7 volts4 ,9 ^! equations v repres5ts ! val5ce ( ! ion4 ,x is cle> t = ! condition ( equilibrium1 9 :i* ,c ,k,ion1 ! pot5tial is #j4 ,fur!r1 = ! pot5tial diff]5ce betwe5 copp] & a cupric salt solution 9 :i* ,cu#b #a1 we w\ld h ,cu1 ,cu#b 7#j4jege _/ #b7 log7#a _/ #h4c;,e#bb7 #ba4jh #j4jege _/ #b #j4fjf volts4 #d4 ,mean+ ( ,e4,p4,elem5t1 ,ion4 ,"u ,e4,p4,elem5t1 ,ion ! table gives ! pot5tial diff]5ce 9 volts1 calculat$ = ! elem5t nam$ & an aque\s solution ( its ion 9 unit conc5tration 7"o gram-ion p] lit]74 ,= in/ance1 = z9c & ,zn#b #a 7#fe4d grams z9c-ion p] lit]71 we h a pot5tial ,e4,p4,zn1 ,zn#b #j4dic4 ,! signs us$1 9 accordance ) ! conv5tion adopt$ 7p4 #bfa71 indicate ! "* ( ! *>ge on ! elem5t electrode 7:i* is nam$ fir/ 9 ! subscript to ,e4,p474 ,= in/ance1 z9c 9 a solution 9 :i* ,zn#b #a w\ld acquire a negative *>ge 7p4 #bff71 ! pot5tial diff]5ce ,e4,p4,zn1 ,zn#b be+ #j4dic accord+ to ! table2 silv]1 imm]s$ 9 a solution 9 :i* ,ag #a1 w\ld acquire a positive *>ge1 ! pot5tial diff]5ce ,e4,p4,ag1 ,ag #a4jdh4 ,! pot5tials giv5 = ! gase\s elem5ts repres5t ! pot5tials ( ! gases "u #gfj mm4 pressure4 #e4 ,pot5tial ,diff]5ces ,calculat$ ) ! ,aid ( ,e4,p4,elem5t1 ,ion4 ,! pot5tial correspond+ to any conc5tration ,c ( a metal ion may be f\nd f ! equation#a ,el41 ,ionv ,e4,p4,el41 ,ion 7#j4jege _/ v7 log,c volts1 & ! pot5tial = any conc5tration ,c ( ! ions ( elem5ts =m+ negative ions is f\nd#ehh accord+ to ,el41 ,ionv ,e4,p4,el41 ,ion 7#j4jege _/ v7 log,c volts4 #f4 ,! ,condition = ,equilibrium betwe5 ,two ,metals & ,_! ,ions1 ,calculat$ ) ! ,aid ( ,e4,p4,elem5t1 ,ion4 ,! condition = equilibrium 9 a sy/em ( two metals & _! ions is det]m9$ by ! fact t ! pot5tial ( ! sy/em mu/ be #j :5 equilibrium is e/abli%$4 ,we h1 = in/ance = ! two metals z9c & copp] & _! ions1 ,zn#b & ,cu#b1 = ,zn ,cu#b ,cu ,zn#b ! condition = equilibrium t ,cu1 ,cu#b ,zn1 ,zn#b #j4 ,accord+ to ! equation giv5 9 #e1 we h1 !n1 = ! condition ( equilibrium1 ,e4,p4,cu1 ,cu#b 7#j4jege _/ #b7 log,cu#b ,e4,p4,zn1 ,zn#b 7#j4jege _/ #b7 log,zn#b #j4 p#bih ,!n 7#j4jege _/ #b7 log7,zn#b _/ ,cu#b7 ,e4,p4,cu1,cu#b ,e4,p4,zn1,zn#b #j4fjf 7#j4dic7 #a4jii4 ,f ! la/ relation we f9d log7,zn#b _/ ,cu#b7 #ch4bbfa1 & !re=e1 = ! condition ( equilibrium1 ,zn#b _/ ,cu#b #a4g;,e#ch4 #g4 ,equilibrium ,con/ants = ,elem5ts ) ,v>iable ,conc5tration4 ,! conc5tration ( a pure metal at a giv5 temp]ature may be consid]$ a con/ant1 except 9 ! case ( extremely ?9 films ( ! metal 7p4 #beh74 ,! conc5tration ( hydrog51 & ( ! non-metallic elem5ts giv5 9 ! table1 is v>iable1 & ,k,ion has a def9ite value only :5 ! conc5tration ( ! elem5t is def9$ 7see ! prec$+ table1 footnotes #c1 #d1 p4 #bie74 ,= c]ta9 e/imations ! equilibrium con/ants1 :i* %[ ! relation betwe5 ! two v>iables1 namely ! conc5tration ( ! elem5t & t ( its ion1 are v helpful 7see pp4 #bgd & #bge74 ,9 ! foll[+ table "s ( ! m important equilibrium con/ants ( ?is nature are giv54 ,,table ,,( ,,equilibrium ,,con/ants4 ,elem5t4 ,kequil44 ,hydrog53 ,h#b 3 ,h#b #e4f;,e#i ,oxyg53 ,,ho#d 3 ,o#b #h4b;,e#di ,*lor9e3 ,cl#b 3 ,cl#b #b;,e#fj ,iod9e,a3 ,i#b 3 ,i#b #e4f;,e#bi ,,table ,,note3 ,a4 ,! value ( ! con/ant1 z giv51 is only an approximate e/imation 7p4 #bgc74 ,! significance ( ! con/ants is indicat$ by ! ratios giv5 9 ! table4 ,! relation ( ^! con/ants to ^? giv5 9 ! fir/ table may be se5 f ! foll[+ illu/ration4 ,= hydrog5 we h ,h#b #b ,h4 ,! fir/ table tells u t hydrog51 at #ah "u atmosph]ic pressure1 is 9 equilibrium ) its ion :5 ! conc5tration ( hydrog5-ion is #a4eb;,e#e 7"u ,k,ion74 ,n[1 a mole ( hydrog5 at #ah occupies #bb4d #bia _/ #bgc #bc4i lit]s "u atmosph]ic pressure1 & its conc5tration 7p] lit]7 is !re=e #a _/ #bc4i mole4 ,!n equilibrium exi/s1 :5 ,h#b #a _/ #bc4i & ,h #a4eb;,e#e & ,kequil4 ,h#b 3 ,h#b 7#a4eb;,e#e7b #bc4i #e4f;,e#i4 ,,footnotes3 #eec ,^! con/ants are calculat$ f data giv5 9 ,wilsmore's tables 7loc4 cit47 on ! solution t5sion ( hydrog54 ,hydrog51 at #ah "u "o atmosph]e pressure1 produces a pot5tial ( ,h#b1 ,h #j4bgg 7see p4 #bfa1 9 reg>d to ! sign7 aga9/ a solution conta9+ hydrog5-ion 9 a conc5tration ,h #a 7see ! table at ! end ( ?is *apt]74 ,n[1 !re mu/ be "s conc5tration ( hydrog5-ion1 :i* we w call ,c1 ) :i* hydrog5 at #ah & #gfj mm4 pressure is directly 9 equilibrium1 ) ! pot5tial #j4 ,= any conc5tration ( hydrog5-ion ,h1 o!r ?an ,c1 a pot5tial is produc$ accord+ to ,h#b1 ,h #j4jege log7,h _/ ,c74 ,if we ins]t into ?is equation ! values ,h #a & ! pot5tial #j4bgg1 & if we solve ! equation = ,c1 we f9d ,c #a4eb;,e#e4 ,t is ! conc5tration ( ,h1 ) :i* hydrog5 ( "o atmosph]e pressure at #ah is directly 9 equilibrium4 ,s9ce "u ^! conditions ( temp]ature & pressure ,h#b #a _/ #bc4i mole1 we h = ! condition ( equilibrium ,h#b _/ ,h#b ,k 3 7#a4eb;,e#e7b 3 7#a _/ #bc4i7 #e4ee;,e#i ,k4 #eed ,exp]im5tally ! relations = an oxyg5 electrode are mu* m complicat$ ?an = a hydrog5 electrode1 z a result1 app>5tly1 ( ! oxidation ( ! metal 7e4g4 plat9um71 ) ! aid ( :i* ! electrode is prep>$4 ,= a critical review & summ>y ( ! m rec5t results on ?is po9t1 vide ,s*o*1 ,j4 phys4 ,*em41 #ad1 #ffe 7#aiaj74 ,= ! purposes ( ?is book x w be suffici5t to limit our discussion to ! behavior ( an ideal oxyg5 electrode4 #eee ,! bival5t oxyg5 ions1 ,o#b1 comb9e ) hydrog5 ions 7=m$1 = in/ance1 by ! ionization ( wat]7 & =m ! m /able hydroxide ions 7p4 #bdf73 ,o#b ,h ,,ho #b ,,ho1 or simply1 ,o#b ,h ,,ho4 ,!n1 ,o#b ,h _/ ,,ho k & ,o#b k ,,ho _/ ,h4 ,b s9ce we h ,h ,,ho ,k,,hoh = ! ionization ( wat] 7p4 #agf71 we also h3 ,h ,k,,hoh _/ ,,ho & ,o#b 7k _/ ,k,,hoh7 ,,ho#b4 ,by sub/itut+ ?is value = ! conc5tration ,o#b ( ! oxide-ion 9 equation 7#a71 equation 7#b7 is obta9$4 ,! con/ant ,k#b includes !n ! con/ants k & ,k,,hoh4 #eef ,! con/ants are calculat$ f ! e/imat$ pot5tial ( ! oxyg5-hydrog5 cell1 #a4bca volt1 at #ah4 7,vide ,g4 ,n4 ,lewis1 ,z4 phys4 ,*em41 #ee1 #dfe 7#aijf72 ,n]n/ & ,w>t5b]g1 ibid41 #ef1 #ecd 7#aijf72 ,brn/$1 ibid41 #fe1 #ia 7#aijh72 & a summ>y & discussion by ,s*o*1 loc4 cit47 ,at #ah oxyg51 "u "o atmosph]e pressure1 gives an e/imat$ pot5tial ,o#b1 ,,ho #a4ejh aga9/ an acid solution1 9 :i* ! conc5tration ( ! hydrog5-ion ,h #a 7see ! table at ! end ( ?is *apt]74 ,s9ce at #ah ,h ,,ho #j4ha;,e#ad1 ! value = ,,ho 9 ?is acid solution is #j4ha;,e#ad4 ,n[1 = oxyg51 at #ah & #gfj mm41 !re mu/ be "s conc5tration ( hydroxide-ion1 :i* we w call ,c1 at :i* ! t5d5cy ( ! oxyg5 to ionize is exactly balanc$ by ! t5d5cy ( ! hydroxide-ion to =m oxyg5--at ?is po9t ! pot5tial is #j4 ,= any conc5tration ,,ho ( ! hydroxide-ion1 o!r ?an ,c1 a pot5tial w exi/ ,o#b1 ,,ho #j4jege log7,c _/ ,,ho74 ,s9ce = ,,ho #j4ha;,e#ad1 we h a pot5tial ,o#b1 ,,ho #a4ejh1 ^! values c be introduc$ into ! equation & ! latt] solv$ = ,c4 ,we f9d ?us ,c #a4cf;,e#ab1 & oxyg51 at #ah & #gfj mm4 pressure1 w\ld be directly 9 equilibrium ) a solution 9 :i* ,,ho #a4cf;,e#ab4 ,at #ah & #gfj mm4 pressure a lit] ( oxyg5 conta9s #a _/ #bc4i mole1 & ?us we h = ! condition ( equilibrium ,,ho#d 3 ,o#b ,k 3 7#a4cf;,e#ab7d 3 7#a _/ #bc4i7 #h4b;,e#di ,k4 #eeg ,! mo/ conv5i5t =m ( electrode = ?is purpose consi/s 7see ,fig4 #ad7 ( a cyl9d] 7ab\t "o in* long7 ( plat9um gauze1 :i* is fus$ to a glass tube & connect$ ) a wire lead+ ?r\gh ! tube to "s m]cury1 held 9 a small bran* tube1 fus$ into ! ma9 tube ne> its upp] end4 ,! gas is easily conduct$ to ! plat9um gauze electrode ?r\gh su* a tube4 ,! cyl9d] ( plat9um gauze may be made by jo9+ ! ends ( roll$ gauze ) pieces ( molt5 glass4 ,x is coat$ ) plat9um black4 #eeh ,cf4 footnote #a1 p4 #bgh4 #eei ,cf4 footnote #a1 p4 #bgi4 #efj ,see ,o/wald1 ,z4 phys4 ,*em41 #aa1 #eba 7#ahic71 ,arrh5ius1 ibid41 #aa1 #hje 7#ahic71 & ,n]n/1 ibid41 #ad1 #aee 7#ahic71 = a detail$ discussion ( oxyg5-hydrog5 gas cells4 ,= m rec5t "w1 vide ,g4 ,n4 ,lewis1 ,j4 ,am4 ,*em4 ,soc41 #bh1 #aeh 7#aije71 :]e ref]5ces to o!r rec5t inve/igations are giv54 #efa ,cf4 footnote #a1 p4 #bfa1 & pp4 #bgg-bgi4 #efb ,see pp4 #db1 #beb1 = ! expression ( ! *anges z transf]s ( electrons4 #efc ,fr$5hag51 ,z4 anorg4 ,*em41 #bi1 #dbd 7#aijb71 has br\ght int]e/+ exp]im5tal evid5ce ( ! *>g+ ( an electrode ) gase\s oxyg51 :5 f]ric-ion is ! oxidiz+ ag5t 9 aque\s solutions4 ,:e!r ! oxyg51 :i* is lib]at$ by ! action ( ! f]ric-ion on wat]1 #d ,fe#c #d ,,ho #d ,fe#b ,o#b #b ,h#b,o1 is always ! int]m$iate product & ! direct oxidiz+ ag5t 9 aque\s solution1 c h>dly be consid]$ decid$ by ! exp]im5t--x may well be ! product ( a p>allel action1 :i* mu/ take place to a c]ta9 ext5t1 accord+ to ! laws ( equilibrium1 9 a sy/em conta9+ bo? ,fe#c & ,,ho ions4 ,! result h>dly proves t oxyg5 mu/ be ! int]m$iate product 9 ! ma9 action1 :5 f]ric ions act z ! oxidiz+ ag5t4 ,we may consid]1 = in/ance1 a solution conta9+ an iodide & a f]ric salt3 iodide ions h a f> small] aff9ity = _! negative *>ges 7electrons7 ?an hydroxide ions h1 &1 consequ5tly1 w transf] _! negative *>ges 7electrons7 m readily to ! f]ric ions ?an ! hydroxide ions w\ld4 ,! action1 if oxyg5 7 fir/ lib]at$1 w\ld lead to ! same ultimate result1 b ! obs]vation made by ,fr$5hag5 w\ld n prove t ! ma9 action w\ld n nev]!less g by ! %ort] direct pa? r ?an ?r\gh an int]m$iate =mation ( oxyg54 #efd ,accord+ to ! !ory1 t ars5ic acid is an oxidiz+ ag5t because x gives up oxyg5 ( a def9ite pressure1 ?is pressure w\ld be ! m effective1 ! m completely ! oppos+ hydroxide-ion is suppress$ by add$ acid 7p4 #bhj2 see also p4 #bgb1 on ! action ( f]ro-ion on silv]-ion 9 ! pres5ce & 9 ! abs5ce ( fluorides74 #efe ,only ! simple/ =m ( basic ionization ( ars5ic acid is consid]$4 ,int]m$iate ionization into ,z7,,oh7#d1 ,z7,,oh7#cb1 etc4 7see p4 #bdi71 is1 ( c\rse1 to be assum$ 9 any complete inve/igation ( ! subject4 #eff ,ars5i\s acid ,z7,,oh7#c1 or ,h,as,o#b1 z well z its anions ,as,o#cc & ,as,o#b1 may h _! own *>act]i/ic t5d5cies to assume positive *>ges & be oxidiz$ to ars5ic acid & its d]ivatives 7see footnote #a1 p4 #bgj74 ,9 alkal9e solutions ^! t5d5cies1 & ! pot5tials correspond+ to !m1 might well be m important factors 9 det]m9+ ! c\rse ( an action1 ?an ! t5d5cy ( ,z#c to =m ,z#e4 ,! discussion 9 ! text1 :i* deals prim>ily ) acid solutions1 does n exclude su* relations4 #efg ,a millivoltmet] is us$ = ?is exp]im5t4 #efh ,see footnote #a1 p4 #bhd1 9 reg>d to ! int]pretation ( ?is exp]im5t on ! basis ( ! !ory ( lib]ation ( oxyg5 by ars5ic acid4 #efi ,cf4 ,smi?'s ,g5]al ,inorganic ,*emi/ry1 p4 #gab4 #egj ,! ess5tial feature ( ?is po9t ( view 0 fir/ publi%$ by ,abegg1 ,z4 anorg4 ,*em41 #ci1 #ccj 7#aijd71 & ,z4 phys4 ,*em41 #dc1 #che 7#aijc72 vide also ,/ieglitz1 ,am4 ,*em4 ,j41 #ci1 #ea 7footnote7 7#aijh71 & ,qualitative ,analysis ,notes1 ,univ]sity ( ,*icago 7#aije74 ,abegg's view has rec5tly receiv$ support f ,j4 ,j4 ,?omson 9 8 ,corpuscul> ,!ory ( ,matt]1 p4 #aah4 #ega ,h does n *ange its val5ce 7*>ge7 9 ! action1 & yet x appe>s z an ess5tial compon5t 9 bo? /yles ( ! curr5t equations = ! oxidation-r$uction reaction4 #egb ,a some:at simil> developm5t ( ^! relations1 = ars5ic acid1 has be5 f\nd 9 ,abegg's ,anorg4 ,*em41 ,,iii1 #c1 p4 #eeb 7#aijg74 #egc ,lu!r & ,mi*ie1 ,z4 fr ,elektro*41 #ad1 #hbf 7#aijh74 #egd ,! calculation is bas$ on ! results obta9$ by ,lu!r & ,mi*ie4 #ege ,! proportion ( ,,uo#bb conv]t$ into ,u#f w\ld be s m9ute1 t 9 an exp]im5tal det]m9ation ( ! conc5tration ,,uo#bb1 ! conc5tration ,u#f w\ld no d\bt be a negligible quantity4 #egf ,pet]s1 ,z4 phys4 ,*em41 #bf1 #aic 7#ahih74 #egg ,9 o!r in/ances1 ! action ( ! hydrog5-ion 9 facilitat+ & accel]at+ *emical actions 7(t5 call$ its catalytic effect7 has be5 expla9$1 9 a simil> fa%ion1 z be+ bas$ on salt =mation1 foll[$ by ! ionization ( ! salts =m$1 ! active compon5ts be+ ! ions 7vide1 = in/ance1 ,br$ig1 ,z4 fr ,elektro*41 #i1 #aah & #aj1 #ehf 7#aijd7 & ,/ieglitz1 ,report ( ! ,congress ( ,arts & ,sci5ces1 ,/4 ,l\is1 #d1 #bgf 7#aijd7 & ,am4 ,*em4 ,j41 #ci1 #bi1 #dae 7#aijh7 & lat] articles74 ,9 _m ( ^! cases1 ! ion conc5trations ( ! react+ compon5ts h n yet be5 accessible to direct measurem5ts1 b ! viewpo9t has be5 su/a9$ by quantitative /udies ( analog\s reactions1 :i* 7 select$ = /udy1 because ! factors involv$ c\ld be measur$ 7cf4 ,/ieglitz1 loc4 cit474 #egh ,u%] & ,prie/ley1 ,proc4 ,roy4 ,soc41 ,b1 #gg1 #cfi 7#aije72 #gh1 #cah 7#aijh74 #egi ,toll5s1 ,b]4 d4 *em4 ,ges41 #ae1 #afce 7#ahhb74 #ehj ,ag ,,nh#cb _/ ,ag7,,nh#c7b #a _/ #ajg4 #eha ,me?yl5e ,,*#b1 itself1 has nev] be5 isolat$1 b d]ivatives ( x are kn[n1 su* z ! cyanides1 ,c7,,nh71 ,c7,,nk7 7see pp4 #ff1 #bcg74 #ehb ,potassium cyanide1 ,c7,,nk71 is a p[]ful r$uc+ ag5t 7see p4 #hi74 #ehc ,pp4 #fe1 #ff4 #ehd ,if a negative *>ge is an electron1 a positive *>ge ! abs5ce ( an electron 9 an atom1 ! bival5t c>bon atom loses two electrons1 :5 x is oxidiz$4 #ehe ,see ,/ieglitz1 ,sci5ce1 #bg1 #ggd 7#aijh74 #ehf ,! oxidation occurs ess5tially 9 ! same mann] z describ$ 7p1 #bib7 = ! action ( =maldehyde on ammoniacal silv] solution1 :5 !y are br\ght toge!r 9 a s+le vessel4 ,9 ! pres5t case1 :]e ! action is us$ to produce an electric curr5t1 !re is a migration ( negative ions into ! =mal9 solution ?r\gh ! salt-bridge 7p4 #bed74 ,= e two silv] ions dis*>g$ on ! electrode 9 ! silv] nitrate solution1 two hydroxide ions are lib]at$ 9 ! =maldehyde solution1 z a result ( ?is migration1 & !y comb9e ) ! oxidiz$ c>bon atom4 ,! oxidation may be express$1 !n1 simply z foll[s3 7,na,o7,,hc #b #b ,,ho 7,na,o7,,hc#b #b ,,ho 7,na,o7,,hc3,o ,h#b,o4 ,by comp>ison ) ! equations giv5 on p4 #bib1 x is evid5t1 t ! only diff]5ce lies 9 ! fact t ! positive *>ges1 9 ! pres5t case1 are c>ri$ to ! =maldehyde salt ?r\gh metal wires & a metal electrode1 :ile previ\sly !y 7 dis*>g$ directly by silv] ions on ! =maldehyde salt4 #ehg ,cf4 ,n]n/1 ,!oretical ,*emi/ry 7#aijd71 p4 #gci1 & ! applications m5tion$ !re4 #ehh ,le ,blanc1 ,elektro*emie1 p4 #bae2 v is ! val5ce ( ! ion4 p#bii ,,*apt] ,,xvi ,,sy/ematic ,,analysis ,,= ,,acid ,,ions ,! sy/ematic analysis = acid ions is made on a plan diff]+ 9 an important p>ticul> f ! sy/ematic analysis = metal ions4 ,! latt]1 z has be5 se51 are divid$ into gr\ps1 :i*1 by precipitation or solution ( *>act]i/ic salts1 are successively sep>at$ f subsequ5t gr\ps1 be=e ! isolat$ gr\ps are analyz$4 ,t is1 9 g5]al1 a gr\p ( metal ions is exam9$ 9 ! abs5ce ( ! ions ( all o!r gr\ps4 ,acid ions are also divid$ into gr\ps1 b1 z a rule1 ! gr\ps are n sep>at$ f ea* o!r = analysis4 ,! reason = ?is diff]5ce 9 proc$ure is f\nd1 *iefly1 9 ! fact t =eign acid ions int]f]e#ehi to a small] degree ) ! specific te/s = ! ions ( a gr\p1 ?an is ! case 9 ! analysis = metal ions4 ,gr\p+ ( ,acid ,ions4--,:ile !re is g5]al agreem5t1 among ! mo/ important sy/ems ( analysis1 9 ! gr\p+ ( metal ions1 !re is notable v>iation 9 ! way 9 :i* acids are gr\p$ by diff]5t au?ors4 ,we %all conf9e ourselves "h to ! consid]ation ( two diff]5t modes ( g5]al proc$ure & n discuss diff]5ces 9 m9or details4 ,if acids 7 pres5t only 9 ! =m ( ! free acids or ( _! alkali salts1 ! division into gr\ps c\ld naturally & pr(itably be made to include gr\ps1 :i* are id5tifi$ by reactions c>ri$ out 9 neutral or alkal9e solution1 z well z by su* z are made 9 acid solutions4 ,n[1 cations o!r ?an ! alkali ions are liable to int]f]e ) te/s design$ = alkal9e or neutral solutions4 ,= in/ance1 a gr\p ( acid ions1 9 :i* ! phosphate-ion is includ$1 is *>act]iz$ by ! fact t ! acids =m b>ium salts1 :i* are soluble 9 acid b n 9 neutral or alkal9e solutions4 ,! abs5ce or pres5ce ( su* a gr\p may be recogniz$1 if no cations o!r ?an ! alkali metal ions are pres5t1 by ! addition ( b>ium *loride to ! solution & by c>eful neutralization ( any free acid1 by ammonium p#cjj hydroxide4 ,b>ium phosphate & ! b>ium salts ( ! o!r acids ( ! gr\p w be precipitat$1 if _! ions are pres5t4 ,x is cle>1 h[ev]1 t a numb] ( metal ions mu/ int]f]e ) ! te/4 ,= in/ance1 a solution ( alum9ium nitrate or ( f]ric *loride1 treat$ ) b>ium *loride1 & ) ammonium hydroxide to neutralize ! acid pres5t 9 ! solution z a result ( ! hydrolysis ( ! salt1 w\ld give a precipitate ( alum9ium hydroxide or ( f]ric hydroxide1 & n ( b>ium salts4 ,! =mation ( a precipitate "u ^! conditions evid5tly w n con/itute any basis :atev] = rea*+ a conclusion z to ! pres5ce or abs5ce ( acid ions1 su* z c =m precipitates ( b>ium salts "u ! same circum/ances4 ,sy/ematic ,analysis = ,acid ,ions1 ,bas$ on ! ,removal ( ,metal ,ions o!r ?an ! ,alkali ,metal ,ions4--,on acc\nt ( ?is k9d ( int]f]5ce1 by cations o!r ?an ^? ( ! alkali gr\p1 ) a numb] ( gr\p & specific te/s = anions1 t may be made 9 neutral or alkal9e solutions1 provision is made1 9 mo/ sy/ems ( analysis1 = ! removal ( su* ions by prop] treatm5t ( ! sub/ance "u exam9ation ) sodium c>bonate4 ,int]f]+ metal ions are !reby conv]t$ into c>bonates or hydroxides :i* are insoluble 9 wat]1 :ile ! acids =m sodium salts :i* pass into solution 9 wat]4 ,occasionally1 rec\rse is also tak5 to hydrog5 sulphide to remove ions ( ! ars5ic & copp] gr\ps4 ,! treatm5t ) sodium c>bonate1 :ile advantage\s 9 c]ta9 cases1 is n uni=mly successful#eij3 x is also frequ5tly complicat$ by ! pres5ce ( amphot]ic bases or ( organic sub/ances1 & frequ5tly dem&s treatm5ts & te/s beyond ^? made ) ! solution ?us prep>$4 ,fur!rmore1 if a gr\p is f\nd to be pres5t1 say a gr\p ( acid ions =m+ b>ium or calcium salts insoluble 9 wat]1 b soluble 9 acids1#eia all ! acids ( ! gr\p1 :i* h n be5 f\nd to be pres5t or abs5t 9 ! analysis = metal ions1#eib mu/ be specifically p#cja te/$ =1 al?\gh !y may all be abs5t & ! only repres5tative ( ! gr\p pres5t may be an ion previ\sly f\nd 9 ! analysis = metal ions4#eic ,!n1 too1 :5 ! gr\p is f\nd to be abs5t by ! gr\p te/1 m s5sitive te/s = "s ( ! acid ions ( ! gr\p mu/ /ill be made to insure _! complete abs5ce4#eid ,:ile mu* may be said 9 favor ( ! sy/ematic analysis = acid ions1 bas$ on ! prep>ation ( a solution conta9+ only ! alkali salts ( ! anions1 & :ile "o %\ld be famili> ) ! plan & be able to h rec\rse to x at w1 yet ! drawbacks m5tion$ sugge/ ano!r basis = ! analysis4 ,sy/ematic ,analysis = ,acid ,ions 9 ,acid ,solution4--,if ! sy/ematic analysis = acid ions is c>ri$ out entirely 9 acid solutions1 int]f]5ce ( cations ) te/s = anions is r>ely met ) & 9 ^? r>e cases may be easily provid$ aga9/4 ,su* a me?od ( sy/ematic analysis 9 acid solution is frequ5tly m direct & m conv5i5t ?an a me?od bas$ on ! removal ( cations o!r ?an ! alkali metal ions4 ,almo/ all ( ! mo/ *>act]i/ic te/s = anions1 z x is1 are c>ri$ out 9 acid solutions1 & only a v few good te/s1 :i* mu/ be made 9 neutral or alkal9e solution1 are sacrific$ by plac+ ! emphasis on ^? c>ri$ out 9 acid solutions4 ,! me?od1 on ! :ole1 has prov$ a "t-sav+ & conv5i5t "o1 )\t loss 9 ! tru/wor?9ess ( ! results4 ,desirability ( ,exp]i5ce ) ,bo? ,me?ods4--,x is desirable to h exp]i5ce ) bo? me?ods1 & to le>n by su* exp]i5ce1 :5 to h rec\rse to ! "o or ! o!r me?od4 ,sugge/ions z to ! *oice ( me?od are giv5 9 ! ,laboratory ,manual1 p4 #aai4 ,! ,gr\ps ( ,acid ,ions4--,! arrangem5t ( ! acid ions into gr\ps1 = analysis 9 acid solution1 does n diff] 9 any ess5tial respect f ! arrangem5t bas$ on ! use ( solutions ( sodium salts ( ! acid ions--only "o gr\p te/1 :i* mu/ be made 9 neutral solutions1 is omitt$ :5 ! acid solution is us$1 & ! individual memb]s ( ?is gr\p are te/$ p#cjb =1 specifically4 ,z t is also v frequ5tly necess>y :5 solutions ( sodium salts are us$1 no notable sacrifice 9 conv5i5ce is made4 ,s9ce ! gr\p+ = bo? me?ods ( analysis may be made ! same1 ! foll[+ gr\p+ ( acid ions has be5 adopt$4 ,only ! gr\p *>act]i/ics are giv52 ! memb]s ( ! gr\ps are describ$ 9 detail 9 ! ,laboratory ,manual 7,"p ,,iii74 ,i4 ,ions ( ,amphot]ic ,acids & ( ,relat$ ,acids4 ,?is gr\p includes ^? acids ^: amphot]ic "*1 or ^: ready r$uction by hydrog5 or ammonium sulphide1 leads to _! be+ f\nd1 or indicat$1 9 ! sy/ematic analysis = metal ions4 ,,ii4 ,! ,c>bonate ,gr\p4 ,?is gr\p includes ^? acids ^: physical prop]ties 7insolubility71 or ! physical prop]ties ( decomposition products ( :i* 7c>bon dioxide is a decomposition product ( c>bonic acid71 usually lead to _! discov]y 9 ! c\rse ( ! prep>ation ( solutions or ( ! analysis = cations4 ,,iii4 ,! ,sulphate ,gr\p4 ,! b>ium salts ( ?is gr\p ( acid ions are insoluble 9 acid solution4 ,b>ium nitrate1 add$ to a solution acidifi$ ) nitric acid1 is ! gr\p reag5t4 ,,iv4 ,! ,*loride ,gr\p4 ,! anions ( ?is gr\p =m silv] salts1 :i* are insoluble 9 nitric acid4 ,silv] nitrate1 add$ to a solution acidifi$ ) nitric acid1 is ! gr\p reag5t4 ,v4 ,! ,phosphate ,gr\p4 ,a te/ = ?is gr\p1 z a :ole1 c be made only if cations o!r ?an ! alkali metal ions are abs5t3 ! b>ium salts ( ! acid ions ( ! gr\p are insoluble 9 neutral1 b soluble 9 /rongly acid1 solutions4 ,b>ium nitrate1 us$ ) a neutral solution1 is ! gr\p reag5t 9 ! abs5ce ( metal ions o!r ?an ! alkali metal ions4 ,9 ! pres5ce ( o!r cations1 ! ?ree memb]s ( ! gr\p1 :i* are n f\nd 9 "s o!r gr\p1#eie namely3 phosphate1 borate & fluoride ions1 are te/$ = specifically1 & ! gr\p te/ omitt$4 ,phosphate-ion is te/$ = 9 nitric acid solution1 9 ! same solution z is us$ = ! te/s = gr\ps ,,iii & ,,iv4 p#cjc ,,vi4 ,! ,nitrate ,gr\p4 ,! salts ( ! acids ( ?is gr\p are readily soluble 9 wat] & specific te/s = ! acid ions are made2 !re is no gr\p te/4 ,,vii4 ,! ,gr\p ( ,organic ,acids4 ,?is gr\p ne$ only be consid]$ :5 a te/ = organic matt] reveals its pres5ce4 ,applications ( ,physico-,*emical ,pr9ciples & ,!ories4--,! physico-*emical pr9ciples & !ories1 :i* h be5 develop$ 9 ! previ\s *apt]s1 naturally apply also to ! reactions by :i* acid ions are id5tifi$4 ,9 _m cases su* *>act]i/ic reactions are id5tical ) reactions /udi$ 9 connection ) ! metal ions4 ,= in/ance1 ! precipitation ( silv] *loride1 us$ to id5tify ! silv]-ion 7reag5t1 *loride-ion71 may be us$1 ) c]ta9 precautions1 to id5tify *loride-ion z well 7reag5t1 silv]-ion74 ,9 ! foll[+1 only a few typical & int]e/+ applications ( ! pr9ciples & !ories to acid ions w be giv52 num]\s o!r applications w sugge/ !mselves 9 connection ) ! laboratory "w on ! acids4 ,fractional ,precipitation ( ,salts ) a ,common ,ion4 ,= saturat$ solutions ( silv] *loride1 bromide & iodide1 we h1 accord+ to ! pr9ciple ( ! solubility-product#eif3 ,ag#a ,cl#a ,k,ag,cl #a;,e#aj2 ,ag#b ,br#b ,k,ag,br #d;,e#ac2 ,ag#c ,i#c ,k,ag,i #c;,e#af4 ,= a solution saturat$ simultane\sly ) ! ?ree silv] salts1 ! value ( ! conc5tration ( ! silv]-ion is ! same 9 ! ?ree solubility-products 7see p4 #afd74 ,consequ5tly1 = su* a solution1 ) :i* ! ?ree solid salts are 9 equilibrium1 ! ratios ( ! conc5trations ( ! anions mu/ be3 ,cl 3 ,br 3 ,i ,k,ag,cl 3 ,k,ag,br 3 ,k,ag,i #c #aje 3 #acjj 3 #a4 ,t is1 if silv] nitrate is add$ to a mixture ( iodides1 bromides & *lorides1 silv] iodide mu/ be precipitat$ fir/1 until ! conc5tration ( bromide-ion1 9 solution1 is #acjj times z great z ! conc5tration ( ! iodide-ion left 9 solution4 ,!n bromide & traces ( iodide ( silv] w be precipitat$1 until ! conc5tration ( *loride-ion is #cjj1jjj times z great z ! conc5tration ( iodide-ion & "s #bej times z great z ! conc5tration ( ! bromide-ion4 ,9 o!r words1 if silv] nitrate is add$ gradually to su* a mixture1 iodide-ion & bromide-ion w be almo/ completely remov$ f solution be=e a precipitate ( silv] *loride c be 9 equilibrium ) ! solution4 ,?is gives u a conv5i5t & rapid me?od ( detect+ *lorides1 if pres5t1 p#cjd 9 m ?an small quantities1 ) iodides & bromides4 ,silv] nitrate1 a few drops at a "t1 is add$ to ! solution & ! mixture vigor\sly %ak5 aft] ea* addition4 ,z long z a yell[ 7,ag,i7 or yell[i% 7,ag,br7 silv] salt is precipitat$ on ! addition ( silv] nitrate to ! sup]natant liquid 7! precipitate settles quickly71 silv] nitrate is add$ z be=e2 :5 ! color becomes q pale1 ! solution is filt]$ & silv] nitrate add$ a drop at a "t2 if a pure :ite precipitate results f9ally1 *loride-ion is pres5t 9 ! mixture 7exp474 ,complex ,ions4 ,in/ances ( ! rle ( complex ions 9 ! analysis = acid ions are num]\s4 ,"o ( ! mo/ int]e/+ illu/rations is ! application ( ! equilibrium conditions = ! complex silv]-ammonium-ion 7p4 #bbd7 to ! sep>ation ( silv] *loride1 bromide & iodide4 ,a r m conv5i5t & m s5sitive me?od#eig = detect+ ! ?ree halide ions 9 ! pres5ce ( ea* o!r ?an ! me?od j consid]$1 may be discuss$ f ?is po9t ( view4 ,! condition ( equilibrium betwe5 silv]-ion1 ammonia & silv]-ammonium-ion is express$ 9 ! relation3 ,ag ,,nh#cb _/ ,ag7,,nh#c7b ,k #a _/ #ajg4 ,! conc5tration ( silv]-ion1 :i* may exi/ 9 an ammoniacal solution1 evid5tly mu/ decrease rapidly ) increas+ conc5trations ( ! free ammonia4 ,n[1 let u imag9e only suffici5t free ammonia1 9 solution1 add$ to a mixture ( silv] *loride1 bromide & iodide1 to keep ! conc5tration ( silv]-ion1 :i* c exi/ 9 ! solution1 say at ,ag #f;,e#i1 :i* is j #a _/ #ajj? ( ! conc5tration ( silv]-ion 9 a saturat$ aque\s solution ( silv] bromide4 ,su* a solution ( ammonia1 9 contact ) ! ?ree silv] salts m5tion$1 w dissolve silv] *loride1 if suffici5t is pres5t1 until ,cl ,k,ag,cl _/ #f;,e#i #j4jag mol>4 ,at ! same "t1 silv] bromide w\ld be dissolv$ until ,br ,k,ag,br _/ #f;,e#i #j4jjj1jf mol>4 ,9 o!r words1 silv] *loride c\ld be dissolv$ 9 "s quantity1 :ile silv] bromide is dissolv$ only 9 traces 7! ratio ( ,cl 3 ,br is aga9 ab\t #bej 3 #a74 ,:5 su* an ammoniacal extract is acidifi$ ) nitric acid1 almo/ pure 7:ite7 silv] *loride w\ld be precipitat$ & only traces ( bromide w\ld be lo/4 ,aft] ! extraction ( ! *loride1 an increas$ conc5tration ( ammonia w\ld lead1 simil>ly1 to a solution 9 :i* silv] bromide w\ld dissolve readily & only traces ( ! iodide be lo/1 & ?us a sep>ation ( bromide & iodide may be effect$4 ,9 ,hag>'s me?od1 ! conc5tration ( ammonia1 requir$ to dissolve silv] *loride ) b traces ( bromide1 is atta9$ by ! use ( a solution ( ammonium sesqui-c>bonate1#eih 9 :i* free ammonia is pres5t only 9 small conc5tration1 z a result ( ! hydrolysis ( ! salt4 ,aft] ! p#cje extraction ( ! *loride by ?is solution1 ! bromide is extract$ ) a #e solution ( ammonia4 ,complex ,ions ( ,acid ,ions ) ,o!r ,acids4--,9 ! /udy ( complex ions we f\nd t positive ions 7silv]1 cupric1 etc47 may =m complex positive ions ) ammonia#eii or complex negative ions ) acid ions 7e4g4 ) cyanide-ion74 ,9 ! /udy ( ! acid ions we also meet in/ances ( complexes =m$ by ! union ( two acids to =m a new complex acid4 ,ammonium phosphomolybdate1 an important salt t is extremely useful 9 detect+ ! pres5ce ( phosphate-ion1 is ! mo/ int]e/+ in/ance ( ! salt ( su* an acid1 :i* is met 9 elem5t>y qualitative analysis4#fjj ,ammonium phosphomolybdate1 7,,nh#d7c,,po#d1 #ab ,mo,o#c1 is ! salt ( a complex phosphomolybdic acid1 =m$ f phosphoric acid1 ,o3,p7,,oh7#c1 & molybdic acid1 ,o#b,mo7,,oh7#b1 by a loss ( wat]1 mu* z potassium di*romate is =m$ f potassium acid *romate ,,ko7,cr,o#b7,,oh ,,ho7,cr,o#b7,,ok ,,ko7,cr,o#b7,o7,cr,o#b7,,ok4 ,! only diff]5ce betwe5 ! two actions lies 9 ! fact t1 9 ! case ( ! di*romate1 anhydride =mation occurs betwe5 two molecules ( a s+le acid2 9 ! case ( ! phosphomolybdate1 anhydride =mation takes place betwe5 molecules ( diff]5t acids1 & a mu* l>g] numb] ( molecules is involv$4 ,if we suppose ! comb9ation betwe5 ! two acids to proce$ symmetrically1#fja we may consid] ! foll[+ to be ! action3 ,o3,p7,,oh7#c #c ,,ho7,mo,o#b7,,oh ,,ho7,mo,o#b7,,oh ,,ho7,mo,o#b7,,oh ,,ho7,mo,o#b7,,oh ,o3,p,o7,mo,o#b7,o7,mo,o#b7,o7,mo,o#b7,o 7,mo,o#b7,,oh#c #ab ,h#b,o4 ,int]m$iate complex acids1 conta9+ less molybdic acid1 are no d\bt =m$ fir/ 7! action is a relatively sl[ "o71 & ! action proce$s until ! =mation ( an insoluble salt leads to ! f9al precipitation ( all ( ! phosphate 9 ?is =m4 ,! precipitate %[s ! *>act]i/ic behavior ( an acid anhydride--alkalies dissolve x readily & =m phosphate & molybdate--e4g4 ammonium hydroxide =ms ,,nh#db;,,hpo#d & 7,,nh#d7b,mo,o#d 7exp474 ,di*romates1 9 a simil> way1 are conv]t$ by alkalies into *romates1 an action :i* may readily be foll[$ by ! *ange 9 color 7exp474 ,oxidation & ,r$uction4--,:ile fractional precipitation ( silv] iodide1 bromide & *loride1 & fractional solution ( ! silv] salts 9 ammonia are conv5i5t me?ods = detect+ ! ?ree halide ions 9 ! pres5ce ( "o ano!r1 ! mo/ accurate & mo/ conv5i5t me?ods = ?is purpose dep5d on ! diff]5t s5sitiv5ess :i* iodide1 bromide & *loride ions exhibit t[>ds oxidiz+ ag5ts4 ,( ! ?ree halog5s1 iod9e %[s ! smalle/ t5d5cy to =m its ion 7see ! table1 p4 #bid71 *lor9e ! greate/4 ,vice v]sa1 ( ! ?ree halide ions1 iodide-ion is mo/ readily1 *loride-ion lea/ readily1 oxidiz$4 ,treatm5t ) a mild oxidiz+ ag5t1 su* z f]ric-ion p#cjf 7see ,*ap4 ,,xiv & ,laboratory ,manual "u iodide-ion71 suffices to oxidize iodide-ion to iod9e3 #b ,fe#c #b ,i #b ,fe#b ,i#b4 ,bromide-ion & *loride-ion are left practically unaffect$ by ?is ag5t 7see ,*ap4 ,,xiv74 ,a some:at /rong] oxidiz+ ag5t1 *romic acid 7or its ion ,cr#f1 see ,*ap4 ,,xv71 oxidizes bromide-ion & leaves *loride-ion practically unaffect$3 #b ,cr#f #f ,br #b ,cr#c #c ,br#b4 ,?is me?od ( fractional oxidation =ms "o ( ! mo/ conv5i5t & s5sitive me?ods = detect+ ! ?ree halide ions 9 ! pres5ce ( "o ano!r4#fjb ,we %all discuss "h only "o o!r oxidation-r$uction reaction1 tak5 9 connection ) ! laboratory "w--! oxidation ( hydroiodic acid by exposure to ! air & ! resi/ance to oxidation %[n by an iodide1 su* z potassium iodide1 "u ! same conditions4 ,! foll[+ me?od ( proximate analysis ( ! *ief relations involv$ may also be us$ to int]pret ! contra/ 9 ! behavior ( hydroiodic acid & t ( hydrobromic or hydro*loric acid 7,laboratory ,manual1 q4 v474 ,9 all ( ^! cases ! actual relations are r5d]$ m complex 9 consequ5ce ( second>y reactions1 ?an is indicat$ 9 ! text t foll[s3 x is int5d$ only to outl9e ! mo/ effective ( ! factors involv$ & to illum9ate ! qualitative results obs]v$4 ,oxidation ( ,hydroiodic ,acid by ,air4--,! oxidation ( hydroiodic acid1 or ( potassium iodide1 by ! oxyg5 ( ! air may be consid]$ 7,*apt]s ,,xiv & ,,xv7 to involve prim>ily ! action #d ,i ,o#b #b ,,hoh #b ,i#b #d ,,ho4 7#a7 ,! condition = equilibrium w be ,i#d ,o#b _/ 7,i#bb ,,ho#d7 ,kequil4 7#b7fjc ,a sy/em 9 :i* ,i is directly 9 equilibrium ) ,i#b 7= :i* ,i#ab 3 ,i#ba ,k,i1 ,iod9e #e4f;,e#bi1 at room temp]ature 7p4 #bih77 & 9 :i*1 at ! same "t1 ,,ho is directly 9 equilibrium ) ,o#b 7= :i* at room temp]ature ,,ho#ad 3 ,o#ba ,k,,ho1 ,oxyg5 #h4b;,e#di 7p4 #bih77 w\ld also repres5t a condition ( equilibrium = ! f\r compon5ts4 ,we f9d ?us ,kequil4 ,k,i1 ,iod9e#b _/ ,k,,ho1 ,oxyg5 7#e4f;,e#bi7b _/ 7#h4b;,e#di7 #d;,e#i4 7#c7 ,) ! aid ( ?is con/ant & ( equation 7#b7 we c obta91 at lea/1 an approximate int]pretation ( ! results ( ! exposure ( hydroiodic acid & ( potassium iodide to ! influ5ce ( atmosph]ic oxyg54#fjd ,we may p#cjg calculate1 fir/1 :at conc5tration ( free iod9e w\ld be requir$ to prev5t oxidation ( hydroiodic acid1 9 mol> solution1 by ! oxyg5 ( ! air1 i4e4 to e/abli% equilibrium4 ,we w call x t conc5tration ( ,i#b4 ,z hydroiodic acid is a v /rong acid1 ioniz$ to ! ext5t ( ab\t #hj 9 mol> solution1 we may1 ) suffici5t accuracy = our purpose1 consid] x completely ioniz$ & put ,i #a & ,h #a4 ,s9ce at #be ,h ,,ho #a4b;,e#ad 7p4 #ajd71 we may put ,,ho #ajad4 ,! conc5tration ( oxyg5 9 ! air1 at room temp]ature1 may be consid]$ to be approximately ,o#b 7#a_/e7 7#a _/ #bc4i74 ,ins]t+ all ^! giv5 values 9 equation 7#b71 we h ,i#d ,o#b _/ 7,i#bb ,,ho#d7 #a 7#a_/e7 7#a _/ #bc4i7 _/ 7x#b 7#ajad7d7 #d #aji4 7#d7 ,solv+ = x1 we f9d x #ajbb ,i#b4 ,t is1 free iod9e ( ?is enorm\s conc5tration w\ld be requir$ to prev5t oxidation ( hydroiodic acid 9 mol> solution by ! oxyg5 ( ! air at room temp]atures4 ,x is obvi\s t hydroiodic acid mu/ be extremely s5sitive to oxidation by exposure to air4 ,"o might e/imate1 9 a simil> way1 ! ext5t to :i* hydroiodic acid1 ( a giv5 conc5tration1 w\ld be oxidiz$ by air be=e equilibrium w\ld be rea*$4 ,! process w\ld involve simultane\s *anges 9 ?ree factors--iodide-ion is de/roy$1 iod9e is =m$ & hydroxide-ion increases1 z ! result ( ! neutralization ( hydrog5-ion by ! hydroxide-ion =m$ 9 ! action 7see above74 ,! solution ( ! equilibrium equation is too involv$ = ! elem5t>y purposes ( ?is discussion3 x leads to ! same qualitative conclusion z 0 j rea*$4 ,oxidation ( ,potassium ,iodide by ,air4 ,we may n[ ask :at ! relations w\ld be1 if we us$ a mol> solution ( potassium iodide 9 place ( ! free acid4 ,i & ,o#b w\ld h ! same value z be=e4 ,! solution be+ orig9ally neutral1 ,,ho w\ld at fir/ h ! value 7#a4b;,e#ad7 #a4a;,e#g4 ,b :5 potassium iodide is expos$ to ! air1 if iod9e is lib]at$1 ! solution becomes alkal9e#fje 7,,ho is =m$ accord+ to equation 7#a77 & ! conc5tration ( ,,ho consequ5tly gr[s cont9u\sly great]4 ,we w1 !re=e1 =mulate ! problem z foll[s3 h[ mu* iod9e#fjf mu/ be lib]at$1 by oxidation ( iodide-ion1 9 mol> potassium iodide solution 9 ord] to e/abli% equilibrium8 ,= e two molecules ( iod9e lib]at$1 f\r ,,ho ions are =m$ 7equation 7#a774 ,if we call y ! conc5tration ( iod9e at ! po9t ( equilibrium1 !n #b y is ! conc5tration ( ,,ho at t po9t1 =m$ by ! oxidation process4 ,ins]t+ ! giv5 values#fjg 9 equation 7#b71 we h ,i#d ,o#b _/ 7,i#bb ,,ho#d7 #a 7#a_/e7 7#a _/ #bc4i7 _/ 7y#b 7#b y7#d7 #d;,e#i4 p#cjh ,solv+ = y1 we f9d y #j4jjg4 ,t is1 9 mol> solution1 ab\t #a4d ( ! iodide#fjh w\ld be oxidiz$ 7c>bonic acid & o!r acids be+ exclud$72 9 #e c4c4 7see ,lab4 ,manual1 p4 #gc7 #i milligrams ( iod9e#fji w\ld be lib]at$ to rea* a condition ( equilibrium4#faj ,x is ?us cle> t ! conditions = equilibrium betwe5 a solution ( an iodide & air w\ld be satisfi$1 9 ! case ( an alkali iodide1 by ! lib]ation ( a m]e trace ( iod9e1 :]eas1 z 0 previ\sly %[n1 9 ! case ( hydrog5 iodide1 a v l>ge proportion ( iod9e mu/ be lib]at$ be=e equilibrium c\ld obta94 ,a c>eful comp>ison ( ! two developm5ts %[s t ! diff]5ce 9 result#faj is pla9ly due to ! high] oxidiz+ p[]1 ! high] pot5tial ( oxyg5 7p4 #bhj71 9 acid solutions1 conta9+ only a m9ute conc5tration ( hydroxide-ion1 z comp>$ ) its effici5cy 9 neutral or slightly alkal9e solution4 ,,footnotes3 #ehi ,9 ! few cases :5 !re is int]f]5ce1 x is provid$ aga9/4 #eij ,cf4 ,fres5ius1 ,qualitative ,analysis1 p4 #ebj4 #eia ,! gr\p includes phosphate1 borate1 fluoride1 oxalate1 silicate1 ars5ite1 ars5iate1 *romate & t>trate ions4 #eib ,! ions ( ! amphot]ic acids1 ars5ic & ars5i\s acids1 & *romate-ion1 :i* is r$uc$ by hydrog5 sulphide to *romium-ion1 are f\nd 9 ! sy/ematic analysis = metal ions4 #eic ,! ions ( ! amphot]ic acids1 ars5ic & ars5i\s acids1 & *romate-ion1 :i* is r$uc$ by hydrog5 sulphide to *romium-ion1 are f\nd 9 ! sy/ematic analysis = metal ions4 #eid ,see ,fres5ius1 loc4 cit41 p4 #eaa1 footnote1 & p4 #ebj4 #eie ,o!r acid ions :i* w\ld %[ ! gr\p te/--precipitation ( a b>ium salt 9 a neutral solution--are det]m9$ 9 o!r gr\ps1 z foll[s3 ars5ite1 ars5iate & *romate ions 9 ! gr\p ( amphot]ic acids1 etc4 7,i72 c>bonate & silicate ions 9 ! c>bonate gr\p 7,,ii72 & oxalate & t>trate ions 9 ! gr\p ( organic acids 7,,vii74 #eif ,! con/ants ref] to #ah4 ,! sub9dices are us$ to di/+ui% ! 7unequal7 conc5trations ( ! silv]-ion & ( ! halide ions 9 ! diff]5t solutions ref]r$ to 9 ! text4 #eig ,hag>'s me?od4 ,see ,fres5ius1 loc4 cit41 pp4 #cef & #cgh4 #eih ,see ,fres5ius1 loc4 cit41 pp4 #cef & #cgh1 = ! prep>ation ( ! solution & = details ( ! me?od1 & see ,smi?1 ,g5]al ,inorganic ,*emi/ry1 p4 #eff1 z to ! nature ( ! sesqui-c>bonate4 #eii ,!y also =m complex ions ) sub/ances relat$ to ammonia1 su* z ! organic am9es4 #fjj ,ammonium ars5omolybdate is an analog\s salt 7see ,laboratory ,manual1 ,"p ,,iii74 ,a simil> complex acid1 phosphotung/ic acid1 is us$ 9 alkaloidal analysis4 #fja ,! exact /ructure ( ! complex acid is n kn[n4 #fjb ,9 ! ,laboratory ,manual a second1 simil> me?od is also giv54 #fjc ,x is consid]$ t wat] has a con/ant conc5tration 9 a dilute solution & t = its active compon5ts ,h ,,ho is a con/ant 7p4 #agf74 #fjd ,9 ! calculation :i* foll[s1 :i* is meant m]ely = a r\gh survey1 no acc\nt is tak5 ( ! =mation ( complex ions ,i#c1 or ( ! t5d5cy ( hydroiodic acid to decompose spontane\sly into iod9e & hydrog53 #b ,h #b ,i ,h#b ,i#b1 a reaction :i* c\ld also be /udi$ pr(itably ) ! aid ( ! equilibrium con/ants = ,i#b #b ,i & = ,h#b #b ,h4 ,! value ( ! iodide con/ant is also unc]ta9 7see p4 #bgc74 #fje #d ,k #d ,i ,o#b #b ,,hoh #b ,i#b #d ,k #d ,,ho4 #fjf ,! =mation ( complex ions ,i#c & o!r second>y reactions 7=mation ( hypoiodite1 iodate1 etc47 are ignor$4 #fjg y has s small a value t we may consid] ,i practically un*ang$4 #fjh #j4jjg ,i#b #j4jad ,i4 #fji ,a mole ( ,i#b #b #abg #bed grams2 7#j4jjg #bed #e7 _/ #ajjj #j4jji gram4 #faj ,! t5d5cy ( iod9e to =m hypoiod\s acid1 iodates1 etc41 is n tak5 into consid]ation "h & involves ano!r relation4 ,,index ,numb]s m>k$ 77 ref] to subjects illu/rat$ by exp]im5ts1 heavy numb]s ref] to tables4 ,acetic acid1 #ih1 #aja1 #aaa-aad ,acid ions1 sy/ematic analysis =1 #bii et seq4 gr\ps (1 #cja ,acids1 #ha1 #hb1 #ajj1 #ajd ,acid salts1 #ajc ,alkali gr\p1 #aeh1 #aei ,alkal9e e>? gr\p1 #aeh1 #afb ,alum9ate-ion1 #agb ,alum9ium gr\p1 #aeh1 #ahh et seq41 #aie ,alum9ium hydroxide1 #aga et seq41 #aif ,alum9ium-ion1 #aeh1 #agb1 #ahh et seq4 ,ammonia1 complex ions (1 #baf et seq41 #bbd ionization (1 #hg ,ammonium hydroxide1 conductivity (1 #gg dissociation (1 #afj ionization (1 #gh1 #aad /r5g? z base1 #gh1 #gi1 #afh ,ammonium-ion1 #afa ,ammonium salts1 dissociation (1 #cd1 #aei effect on ammonium hydroxide1 #afh ,amphot]ic acids1 gr\p (1 #cjb ,amphot]ic hydroxides1 #aga et seq41 #ahg1 #ahh1 #aif ,antimony1 ions (1 #agd ,arg5ticyanide-ion1 #bbe ,arrh5ius's !ory ( ionization1 see ,ionization ,ars5ic acid1 #bdg1 #bej1 #bhc ,ars5ic gr\p1 #aeh1 #baj1 #bdb et seq4 ,ars5ic1 ions (1 #aeh1 #agd1 #bdb et seq4 ,ars5ic p5tasulphide1 #bdg ,ars5i\s sulphide1 colloidal1 #abe ,association1 #ai1 #fd ,aurocyanide-ion1 #bcb ,avogadro's hypo!sis1 #cc1 #cd ,avogadro-van 't ,h(f ,hypo!sis1 #ae1 #cg ,azolitm91 #gi ,b>ium c>bonate1 z reag5t1 #aic ,b>ium-ion1 #afb ,bases1 #gi1 #ha1 #aje1 #ajf ,basic salts1 #ajf1 #aid ,bismu?-ion1 #aeh ,boil+-po9t1 #ag1 #cf1 #ch ,borates1 hydrolysis (1 #ij ,brom9e1 #beb ,cadmium-ion1 #aeh complex ions (1 #bbd1 #bbh sulphide1 #bji et seq4 ,calcium-ion1 #afb ,c>bonate gr\p1 #cjb ,c>bonic acid1 #ij1 #ajj ,*emical activity ( ions1 #gb1 #gh1 #hg1 #bcb ( acids1 #ha1 #hb1 #aje ( bases1 #gi1 #ha ( molecules1 #gd1 #hc1 #bcb ( salts1 #gd1 #ajg1 #aaf ,*emical equilibrium1 #ij et seq41 #if & direction ( action1 #aab & pa? ( action1 #bce & physical equilibrium1 #aci et seq4 ( electrolytes1 #ih1 #aaa-aae ,*emical equilibrium1 law (1 #ia1 #id & ionization ( /rong electrolytes1 #ajh factors (1 #ie et seq4 limitations to1 #ie ,*emomet]1 #bec ,*loride gr\p1 #cjb ,*loride-ion1 oxidation (1 #bge1 #bgf ,*lor9e1 #df1 #beb1 #bge ,*romium-ion1 #aeh1 #ahh et seq4 ,*romic acid1 #bhg ,cobalt-ion1 #aeh1 #aib ,cobalticyanide-ion1 #bbi ,cobalt sulphide1 #aib ,colloidal condition1 #abe et seq4 def9ition (1 #acj relations to analysis1 #aca1 #acf solution !ory (1 #abh susp5sion !ory (1 #abi ,colloids1 electric *>ges on1 #aca precipitation (1 #acc protective action (1 #acf1 #acg ,complex ions1 #hh1 #baf et seq4 applications 9 analysis1 #bbj1 #bcj ( acid ions1 #cje ( ammonia1 #baf et seq4 ( cyanide-ion1 #bbe et seq4 ( halide ions1 #bcg ( oxide-ion1 #bch ( sulphide-ion1 #bch1 #bdf organic1 #bch ,conc5tration1 def9ition (1 #ia ,conductivity1 #dd1 #df1 #dg1 #di1 #ea1 #ef p>tial1 see ,mobilities ,copp]1 equilibrium ) cupric-ion1 #beh1 #bfd oxidation (1 #beg et seq4 solution-t5sion (1 #bei ,copp] gr\p1 #aeh1 #aii et seq41 #baj1 #baf et seq4 ,cupric-ion1 complex ions (1 #bbd equilibrium ) copp]1 #beh1 #bfd r$uction (1 #beg sulphide1 #bab ,cupr\s-ion1 complex ions (1 #bbh ,cyanide-ion1 complex ions (1 #hh1 #bbe et seq41 #bcb ,dialysis1 #abh ,dielectric con/ants1 #fb1 #fc ,diffusion1 ( gases1 #bi ( ions1 #ei ( solutes1 #i ,dissociation ( complex ions1 #bai electrolytic1 see ,ionization gase\s1 #cd1 #cf1 #if ,dry salts1 #gd ,electrolysis1 #df1 #eh ,electrolytes1 see ,ionog5s ,electron !ory1 #db ,equilibrium1 see also ,*emical equilibrium & ,physical equilibrium con/ants1 #ie1 #ih1 #bcc1 #bcf1 #bih oxidation & r$uction1 #beh1 #bfe et seq41 #bfg1 #bgc et seq4 ,f>aday's law1 #eh ,f]ric hydroxide1 #abg1 #agj ,f]ric-ion1 #hh1 #bea1 #beb1 #bfi ,f]ricyanide-ion1 #hh1 #bcj ,f]rocyanide-ion1 #hh1 #bcj ,f]r\s-ion1 #hh1 #bea1 #beb1 #bfi ,=maldehyde1 #bhi et seq4 ,fractional oxidation1 #cje1 #cjf ,fractional precipitation1 #afc1 #afe1 #cjc ,fractional solution1 #cjd ,freez+-po9t1 #ag1 #cf1 #ch ,fus$ salts1 #ge ,gold1 #aeh1 #bdb et seq4 colloidal1 #abf see also ,aurocyanide-ion ,gr\ps ( metal ions1 #aeg ,gr\ps ( acid ions1 #cja ,heat1 #ge1 #gf ,het]og5e\s equilibrium1 see ,physical equilibrium ,hydrog51 oxidation (1 #bgg1 #bgh1 #bhj ,hydrog5 *loride1 #cd1 #cg1 #db1 #gb1 #gc1 #hd ,hydrog5-ion1 action on indicators1 #gi1 #aje *emical activity1 #gb-gd1 #ha1 #hb1 #bgh et seq4 conc5tration = precipitation by ,h#b,s1 #bac mobility1 #ed1 #ef ,hydrog5 sulphide1 ionization (1 #aii1 #bde oxidation (1 #bea1 #bed precipitation by1 #ij1 #aii et seq41 #bjc ,hydrol1 #age ,hydrolysis ( salts1 #abg1 #agh et seq41 #aij ,hydroxide-ion1 action on indicators1 #gh1 #gi *emical activity1 #gi1 #ha1 #afh mobility1 #ed1 #ef ,indicators1 #gi1 #afe1 #bad ,in/ability con/ants1 #bai1 #bbd1 #bbf ,iodide-ion1 #hh1 #bgb1 #cje ,iod9e1 #bgc1 #cje ,ionization & *emical activity1 #fi1 #gb1 #gi1 #ij et seq41 #aaf1 #bcb & conductivity1 #dd1 #gg1 #aae & dielectric con/ants1 #fb-fd & electron !ory1 #db & ,f>aday's law1 #eh & osmotic pressure1 #fg & solv5ts1 #fa con/ants1 #ih1 #ajj1 #ajd1 #ajf1 #ajh degree (1 #ej exceptional1 ( c]ta9 salts1 #aae 9 /ages1 #ajj1 #ajb ( acids1 #fi1 #ih1 #ajj1 #ajd1 #ajh ( bases1 #fi1 #aje1 #ajf1 #ajh ( colloids1 #acb ( salts1 #fi1 #gd1 #ge1 #ajg1 #ajh1 #aae !ory ( ,arrh5ius1 #dj1 #da1 #ea !ory ( ,clausius1 #ea ,ionog5s1 #fi ,ion-product1 see ,solubility-product ,ions1 #db *>ges on1 #da1 #eh comb9ation ) solv5ts1 #db1 #fe composition (1 #fi1 #hi migration (1 #de1 #ec1 #ed mobilities (1 #ef ,k9etic !ory1 ( gases1 #bf & osmotic pressure1 #bf ,lead-ion1 #aeh sulphide1 #bab1 #bac ,light1 #gf ,litmus1 #gi ,magnesium hydroxide1 #afh ,magnesium-ion1 #afb ,mangan\s-ion1 #aeh ,mass action1 law (1 #ic1 #if ,m]curic *loride1 #eg1 #aae ,m]curic cyanide1 #aae1 #aaf1 #bca ,m]curic-ion1 #aeh1 #beg ,m]cur\s-ion1 #aeh ,m]cury1 #beg ,me?yl orange1 #gi ,me?yl violet1 #bac ,mobilities ( ions1 #ec1 #ef ,molecul> weights1 #cc1 #cf1 #cg ,n]n/'s =mula1 #bfa et seq41 #bif et seq4 ,nickel-ion1 #aeh cyanide-ion1 #bbi sulphide1 #aib ,nitrate gr\p1 #cjb ,nitric acid1 #bhh ,organic acids1 gr\p (1 #cjb ,organic sub/ances1 complex ions (1 #bch oxidation (1 #bhi et seq4 ,osmosis1 #aj1 #bb1 #bd ,osmotic pressure1 #h et seq4 & ionization1 #dj1 #fg def9ition (1 #aj indirect det]m9ation (1 #af laws (1 #ab-bj measurem5t (1 #aj !ories (1 #cb ,oxalates1 complex ions (1 #bda ,oxidation1 #bea et seq41 #bhb et seq4 by electric curr5t1 #beb def9ition (1 #bea ( organic comp\nds1 #bhi production ( curr5t by1 #bec relation to !ory ( ionization1 #bea et seq4 ,oxidation-r$uction1 rev]sibility (1 #bef1 #bfh et seq4 int]pretations (1 #bea1 #bhb1 #bhf ,oxyg51 oxidation by1 #bgg1 #bgh1 #bhj1 #cje ,oxyg5-hydrog5 cell1 #bhj ,p]manganic acid1 #bhg ,p]petuum mobile1 #ab ,phases1 #aah ,ph5olph?alen1 #gi ,phosphate gr\p1 #cjb ,phosphomolybdates1 #cje ,phosphoric acid1 #ajb1 #acd ,physical equilibrium1 #aah et seq4 & *emical equilibrium1 #aci et seq4 applications ( law (1 #abj law (1 #aah ,plat9um1 #aeh1 #bdb et seq4 ,potassium hydroxide1 #ggha1 #ajf ,potassium-ion1 #aeh1 #afa ,pot5tial diff]5ces1 #bfa et seq4 & conc5trations1 #bfa1 #bfc & osmotic pressures1 #bfa sign (1 #bfa ,precipitates1 see also ,precipitation solution (1 #aea wa%+ (1 #adh ,precipitation1 #abb1 #ade et seq4 & ionization1 #gd1 #ij1 #aeb1 #bbj et seq4 fractional1 #afc1 #afe influ5ce ( a common ion1 #add1 #adf1 #adg influ5ce ( electrolytes1 #add1 #aej ( electrolytes1 #ade ,prim>y ionization1 #aja1 #ajb ,purple ( ,cassius1 #abf1 #acd ,r$uction1 see also ,oxidation by electric curr5t1 #beb def9ition (1 #beb int]pretations (1 #bea1 #bhb1 #bhf production ( curr5t by1 #bec ,salt-effect1 #hb1 #aji1 #aaj ,second>y ionization1 #aja1 #ajb1 #bdf ,silv]1 colloidal1 #abg ,silv]-ammonium-ion1 #bag et seq4 ,silv] bromide1 #bbd1 #cjc ,silv] *loride1 colloidal1 #ach precipitation (1 #aej solubility (1 #bba ,silv] *romate1 #ada1 #afe ,silv] gr\p1 #aeg1 #aii et seq41 #baf et seq4 ,silv] iodide1 #bbd1 #cjc ,silv]-ion1 #aeh z oxidiz+ ag5t1 #bij complex ions (1 #baf1 #bbe ,sodium hydroxide1 #ha1 #ajf1 #agc ,sodium-ion1 #aeh1 #afa ,solubility1 #aba1 #abc1 #adf1 #adg1 #aec1 #aee ,solubility-product pr9ciple1 #ada et seq4 applications (1 #ade1 #adg1 #adi1 #aea d]ivation (1 #aci et seq4 ,solution1 !ories (1 #h1 #cb ,solution ( electrolytes1 #aea ,solutions1 conc5trat$1 #ae1 #cb1 #adb dilute1 see ,osmotic pressure non-aque\s1 #fb1 #gc1 #hd sup]saturat$1 #aba ,solution-t5sion1 electrolytic1 #beh et seq4 con/ants1 #bei1 #bff1 #bid1 #bie ,solv5ts & ionization1 #fa1 #fd & solubility ( electrolytes1 #aed1 #aee ,/r5g? ( acids1 #ajd ,/r5g? ( bases1 #gh1 #ajf ,/rontium-ion1 #aeh1 #afb ,sulphate gr\p1 #cjb ,sulphide-ion1 complex ions (1 #bch1 #bdf conc5tration (1 #bjb oxidation (1 #bea1 #bed ,sulphides1 precipitation (1 #aii1 #bjc et seq4 solubilities (1 #bjc et seq41 #bab ,sulpho-acids1 #bdd et seq4 ,sulpho-bases1 #bdd et seq4 ,sulpho-salts1 #bdc et seq4 ,sulphuric acid1 ionization (1 #ajc ,sup]saturation1 #aba ,sy/ematic analysis1 ( metal ions1 #aeg et seq4 ( acid ions1 #bii et seq4 ,t>t>ic acid1 complex ions (1 #bch ,t91 ions (1 #aeh1 #agd1 #bdb et seq4 ,unsaturat$ comp\nds1 #fd ,uranyl salts1 #bhf ,val5ce1 #ei & precipitat+ p[] ( ions1 #ace ,van 't ,h(f's hypo!sis1 see ,avogadro ,van 't ,h(f's !ory ( solution1 #ab et seq4 app>5t exceptions to1 #ah ,vapor t5sion1 #ag1 #cf1 #ch ,velocity ( action1 #ib ,wat]1 see also ,hydrolysis composition (1 #age dielectric con/ant (1 #fc =mation by electrolytic oxidation1 #bhj1 #bhb ionization by1 #cg1 #da1 #dg1 #fa1 #gc1 #gd ionization (1 #ec1 #ajd1 #ajf1 #agf et seq4 oxonium ions (1 #bch second>y ionization (1 #bdf1 #bgh ,z9c1 #beg1 #bff ,z9c gr\p1 #aeh1 #ahh et seq41 #baj ,z9c-ion1 #bff ,z9c sulphide1 #bjd et seq4 ,,transcrib]',s ,,note4 ,orig9al pr9t$ spell+ & gramm> is g5]ally reta9$4 ,footnotes 7 r5umb]$ & relocat$ to ! ends ( *apt]s4 ,notes to tables 7 left 9 _! orig9al locations4 ,"s ma!matical & *emical =mulas & equations 7 modifi$ 9 =mat or re>rang$4 ,text orig9ally pr9t$ 9 italics is h]e9 m>k$ ?us4 ,orig9ally bold text is h]e9 l ?is4 ,orig9al small caps is h]e9 all capitals4 ,?is book uses _m uncommon ,unicode *>act]s1 & c>eful selection ( ! ebook read] s(tw>e & font us$ to view x is necess>y4 ,"s ( ! uncommon *>act]s n already m5tion$ are3 ,u#bbif 2 ,u#bbie 2 ,u#bba;,e 2 ,u#bba;,b 2 ,u#bbab 1 ,m9us ,sign2 ,u#ba;,c#d 2 ,u#baib 2 ,u#begb 2 & ,u#bega 4 ,! use ( a monospac$ font is important = ! data tables1 & = "s *emical =mulas4 ,on ! o!r h&1 ! ,?9 ,space ,u#bjji is us$ ae/hetically 9 mo/ ( ! *emical & ma!matical equations1 & an exact monospac$ font w n display ,?9 ,space correctly4 ,adobe's ,s\rce ,code ,pro is an unusual monospace font t does display ,?9 ,space1 ! *emical =mulas1 & ! data tables correctly4 ,deja,vu ,sans ,mono is ano!r good *oice1 b x does n display ,?9 ,space correctly4 ,! notation ,dx signifies ,d subscript x4 ,! notation ,dy signifies ,d sup]script y4 ,9 unambigu\s cases :]e ! sup]script$ text is a s+le digit expon5t 7#j-i71 ?is is simplifi$ to ,dy4 ,! ar*aic =m ( sci5tific notation exemplifi$ by #j4jdac1 is h]e9 simplifi$ ei!r to decimal =m--#j4jjjjac 9 ?is example--or to mod]n sci5tific ,e notation1 #a4c;,e#e4 ,9 ?is1 ,e means times t5 rais$ to ! p[] (4 ,fur!rmore1 ,e notation has also be5 sub/itut$ h]e9 = mo/ numb]s orig9ally pr9t$ l ?is3 a #aj;b4 ,! "n van't ,h(f 0 *ang$ to van 't ,h(f ?r\gh\t2 likewise ,van't to ,van 't4 ,! hyph5 is us$ inconsi/5tly ?r\gh\t ! book1 9 words su* z hydrog5-ion v]sus hydrog5 ion or non-ioniz$ v]sus nonionizi$4 ,^! h be5 reta9$4 ,! ^w difficulty 0 sometimes employ$ z an adv]b2 h]e9 x is conv]t$ to difficultly 9 ?is usage4 ,page #de3 ,*ang$ p]mangante to p]manganate4 ,page #ha3 ,remov$ ! unmat*$ "r p>5!sis f ! diff]5ce 9 ionization betwe5 potassium hydroxide & ammonium hydroxide744 ,page #ajd3 ,9 ! table1 ,hydrog5 sulphide 0 *ang$ to ,h#b,s to meet maximum l9e-l5g? con/ra9ts = ?is ebook4 ,fur!rmore1 ! table notes 7 reord]$ & r5umb]$ to mat* ! sequ5ce ( note an*ors 9 ! table4 ,! an*or 9 ! table title orig9ally l9k$ to a footnote in/ead ( a table note2 ?is footnote 0 conv]t$ to a table note 7! fir/ "o74 ,page #ajf3 ,! label = ! six? note to ! table ,! ,ionization ,con/ants ( ,bases 0 *ang$ f #c to ,f4 ,page #aag3 ,! *emical reaction s*ema1 orig9ally compris+ two balanc$ equations & two unbalanc$ equations us+ v]tical arr[s has be5 re>rang$ into f\r balanc$ equations1 ) horizontal arr[s4 ,su* re>rangem5ts h be5 sil5tly p]=m$ else:]e4 ,on page #bag1 a s*ema ( ?ree equilibrium equations 0 sep>at$ into ?ree equations1 & also remov$ f its emb$d$ location )9 its p>agraph l9e4 ,page #aag3 ,! pr9t$ symbol t might be describ$ z normal leftw>d arr[ ov] rightw>d d>k arr[ 7or heavy arr[7 has be5 repres5t$ h]e9 ) a m readily available "* --! ,unicode "* ) hexadecimal numb] #bidb 7,u#bidb71 rightw>d arr[ ov] %ort leftw>d arr[4 ,! same "* is us$ h]e9 = ! pr9t$ symbol :i* might be describ$ z d[nw>d d>k arr[ left beside upw>d %ort arr[ "r--! equations hav+ be5 re>rang$ into a horizontal =mat--& also = rightw>d d>k arr[ ov] leftw>d arr[4 ,a diff]5t "* ,u#bidc repres5ts normal rightw>d arr[ ov] heavy leftw>d arr[4 ,page #abe3 ,9 ! reaction ( ars5i\s oxide ) hydrog5 sulphide1 *ang$ ,h#c,s to ,h#b,s4 ,page #adf3 ,9 ! table head+1 ,,*#c;,,coo- 0 *ang$ to acetate to save space4 ,! same ?+ 0 done 9 ! table on page #adf4 ,page #aeg ,m5delejeff *ang$ to ,m5deleff4 ,page #ahh1 second footnote 7#chj73 ,! pr9t$ /ructure = glycocoll a4k4a4 glyc9e 0 %[n r\ghly z foll[s3 ,h#c,n4,,*#b;,,coo ) a l9e drawn betwe5 ! ,n & ! "r-h& ,o4 ,?is has be5 h]e9 mod]niz$ to ,h#c,n4,,*#b4;,,coo1 %[+ explicitly ! zwitt]ion /ructure 7! second full /op add$ to emphasize t ,,coo is a unit74 ,! html & mobile v]sions reproduce ! orig9al /ructure4 ,page #aig3 ,*ang$ ,al,o#c y to ,al,o#cc y4 ,page #bbf etc43 ,bo? =ms ,bodla5d] & ,bodlnd] are reta9$4 ,page #bci3 ,! lett]s orig9ally und]scor$ are h]e9 m>k$ ) ,u#bjag1 ,d\ble ,l[ ,l9e1 e4g4 ,,oh4 ,page #bdf3 ,*ang$ saponify+ e/]s 7p4 #hja7 to saponify+ e/]s 7p4 #ha74 ,page #beb3 ,sub/itut$ = a symbol t might be describ$ z circl$ epsilon4 ,page #bhc3 ,9 ! equation %[+ ! oxidation ( z9c by cupric ion1 ! upw>d arr[ orig9ally %[n beside ! symbol = copp] metal is *ang$ to d[nw>d arr[4 ,page #caj3 ,! ref]5ce = mobility ( ,hydroxide-ion 0 *ang$ f #aef to #ef4