134 



BUTLER 



ART. D 



in solutions of chloroform (Si) and acetone (^2) calculated from 

 the partial vapour pressures determined by Zawidski.* For 

 both components, the activity is taken as unity in the pure 

 liquid. 



TABLE I 



Activities and Activity Coefficients in Solutions of Chloroform 



AND Acetone (35.17°C.) 



The activities of a non-volatile component of a binary solution 

 can be determined from the activities of a volatile component 

 by means of the Gibbs-Duhem equation : 



Since 



and 



we have 



Wid/il + W2C?/i2 = 0. 



At , 



At ^ 

 JU2 "= Ala" + ^ log a2, 



— d log ai + — d log ai = 0. 



(169) 



Z. physikal. Chemie, 35, 129 (1900). 



