Molecular Thermodynamics. 631 



so that accurate data, whether solvent-separation data or 



solute-separation data, for low concentrations ( below —=- ) 



at different temperatures would enable us to calculate u', 

 and compare the experimental value with the theoretical 

 value calculated by Milner from dynamical theory. 



Mixtures of Strong Electrolytes. 



It will be o£ interest, now, to consider the extension of 

 this theory of electrolytes to the more general case of a 

 mixture of strong electrolytes, particularly as experimental 

 data on this head are forthcoming. 



Consider a very dilute solution of various univalent ions, 

 in total number %rii, and in total concentration 2^. These 

 quantities correspond to 2n and to 2c respectively in the 

 simple case of a single electrolyte. 



In such a solution we may regard all the ions as point- 

 charges, and (as we have seen, in that ca^e) express the total 

 ttr<j>(r), (cf. (79), as 



(itn^Aitc^i (87) 



We may conveniently write 



i2c!=A (88) 



the total equivalent concentration, or total concentration of 

 ions of one sign, so that 



^9=* (89) 



And, neglecting again the general volume terms, we have 

 \]=M n + Xn 1 u 1 -nM u'C i K . . . (90) 



Y=M. v ±Xn 1 v 1 , (91) 



so that 



^ = M o (0M + 2RC») + 2wi(0i-Rlogc 1 )-JaM o / C i ', (92) 

 and thence 



g -*. -R { log,. + 1^0/} J 



K • • (93) 



that is i = 2+j [ <t>'C i i , .... (94) 

 logY S =!fC> (95) 



