84 



If k\ is large compared willi c and FT. we may write 



' c—H ■ 



Now, tins expression is identical with Ostwai.d's diiulioii law, 

 /; ^ «7(1 — «)''. ^s shown by snbstilnlion of n^Hjc and v:=Ajc. 



This simplification will be permissible in the case of snlplioacelic 

 and siilphopropionic acids, for which, in a previous paper ') the lirsl 

 dissociation constants were found to be 0.58 and 0.57 respectively. 



Now, the solutions of the acid salts of these compounds in various 

 concentrations were compared, by the aid of indicators, at room 

 temperature, vvitli the bufiler solutions of Sorknskn and of Clakk. 



In the following table v i."i the numl)re of litres, containing 1 

 gram molecule of the acid salt, /> is the hydrogen exponent 

 {p = — loif H) H is the concentration of the hydrogen ions in gram 

 ions per litre, « is the degree of dissociation of reaction II («=: //i;) 

 and the equilibrium constant derived therefrom is k^ = <t'/(l — ft)v. 



The concordance of the constants at various dilutions is very 



satisfactory, as the indicator method does not allow a great accuracy. 



However, for great concentrations a correction might be made 



1) These Proceedings 25, 359 (1922). 



