DEPRESSION OF THE FREEZING-POINT 239 



Evidently, therefore, it is the latter alternative which repre- 

 sents the true mode of formation of these salts, and we must 

 conclude that in the neutralization of bases the dicarboxylic 

 radicals play a leading part, just as, in the neutralization of 

 acids, the diamino radicals play a leading part. 



We have seen that in the formation of ovomucoid chloride, 

 containing 45 X 10~" equivalents of acid per gram, only one of 

 the — COH.N— bonds which is opened up suffers the introduction 

 of an HCl molecule. In this case, therefore, if the above reason- 

 ing has been correct, the freezing-point depression due to the dis- 

 solved salt should be either twice or three times that of a solution 

 of the molecular concentration of the neutralized acid according 

 as to whether the formation of the salt is represented by the 

 equation: 



H CI 

 ++ \ / 



, coh.n. /coh ^n^ 



r; ;r + hci + H20 = r; +++ ':r 



^ coh.n ^ ^coh ^n^ 



/ \ 

 H OH 



or by the equation: 



H C 



R-COH.N. ^N^^ 



^ R + HCH- H2O = 2 R.COH++-h : R 



R-COH.N^ <^N^ 



H OH 



that is, according as to whether the diamino acid radicals in the 

 ovomucoid molecule are directly united with both carboxyls of 

 dicarboxylic acid radicals, or with only one or with monocar- 

 boxylic acid radicals. The experimental fact is that the freezing- 

 point-depression of a 0.018 m. solution of HCl containing 4 per 

 cent of ovomucoid (1 gram per 45 X 10~^ equivalents) is 0.09 db 

 0.005 degree, corresponding to a 0.055 m. solution, or almost 

 exactly three times the molecular concentration of the neutralized 

 acid. 



Hence we may conclude that the formation of this salt is repre- 

 sented by the latter of the above two equations and that in ovo- 

 mucoid the diamino radicals are not directly attached to both carboxyls 

 of dicarboxylic radicals. 



