(434 ) 



Nernst's formnla fur A, obtained in a different manner, is identical 

 with onr formula (5). (As Nernst's E =z V^ — V^, our Z- = — E). 

 For if wc re|)lac<^ n' ,. — .u'. bv RT hxi Kk J^nd u'„ — u' , bv 



RT lv<j Ka, then (Ö) passes into 



71*2' , ca.. RT , 07„ 

 Z^ := lo(l Kk — ' ^= — ^"'/ ^^ ^7 — '- 1 



and this is Nernst's expression. "As has already been observed, the 

 quantities Kk ^iiid Kri are the so-eallcd "partilion-eoeflieients" of tlic 

 positive and negative Ions. For instance for the positive Ions we should 

 have, wlien ecpiilibrium of partition occurs : 



or 



Ao A, Cj^^ 



^K 



so that we obtain — - =z Kk ■ The same for tlie ne.^ative Ions. 



The relation, p:iven bv Nernst ') 



KkXKci^j} X^Ka, 



in which Kkci is the coefKicient of partition of tlie Jieutral KCl- 

 molecules, and (\ and ( ._, arc the (lissocitftionvonsUmis in tlie two pliases, 

 follows directly from tlie thermodynamical meaning of these (piantities. 

 For if we Avrite this relation in the form 



RT [log Kk-\-Io<i Kr[\ = RT \lo<j (\ — lo>i C^ + lo<i RkciI 

 it passes, taking into account equation (a) and the relations 



RTlo<jKKa^l^j,,i-li,,ar ^^^'^^''' ^^=f'Kar^'Kr''a' 

 RTlo;,C, = (ïj^,.^-ti:j^-li^,^, 



immediately into tlie identity 



(^^'a,- (''k) + (^^Vv, -fS,7, ) = ((''k. 7. -^'/M -'''CA ) - 



- ^f'Kar^^Kr^'r,) + (^'Kcir^'xa)- 



Not the formula (5), but the formula (6) or (6^/), derived by us from 

 (5), deserves however the preference, because the concentrations of 

 the Ions have l)een eliminated therein, and an expression has been 

 obtained, in which only the coefficients of partition Kk and /vc7 occur. 



III. If the dissolved electrolvte has now distributed itself so, that 



1) Z. f. Ph. Cb. 8, 138 (1891). 



