20 NOYES-POTTER— THE VALENCE OF [April 24. 



may be replaced by chlorine by the action of nitrosyl chloride 

 and considered this an argument against the inner salt formation. 

 Somewhat later Carrara and Rossi^ based an argument for the 

 inner salt structure on the conductivity of betaine hydrochloride, 

 (CH3)3NC1CH2C02H. From the values found they considered 

 that the salt was almost completely hydrolyzed to hydrochloric acid 

 and betaine, (CH3)3NCH2CO. Winkelblech^" points out, however, 



O 



that if betaine hydrochloride is in reality hydrolyzed the conductivity 



of the solution should be the same as that of the equivalent amount 



of 'hydrochloric acid while both Bredig's measurements and those 



of Carrara and Rossi gave a conductivity scarcely more than one 



half as great There can be no doubt, of course, that the anhydride 



of betaine, (CH3)3NCH2C02, has the structure of a salt, but no one 



seems to have determined whether this is monomolecular or di- 



molecular. Our results given below indicate that a solution of an 



amino acid which gives no inner salt may still contain the acid 



mostly in the monomolecular form. 



Winkleblech^^ discusses the hydrolysis of an amino acid on the 



basis of conductivity data for weak acids, weak bases and water. 



It does not seem possible from conductivity data, however, to de- 

 termine whether the acid is in the form of an inner salt. 



.CO, 



R< 



^NH3 



CO,H XO,H 



<, in the unionized state, R<^ or R"^ 



the 



.c6; 



form of the double, amphoteric ion R<f or in the form of a 



NH3+ 



CO2-NH3. 

 bimolecular salt, R^ yR. The hydrogen and hydroxyl 



^NHg— CO^'^ 

 ions of the amphoteric form would, of course, combine to form 

 water and if the acid and basic functions were of equal " strength " 

 the solution would react neutral. None of these forms would show 

 any conductivity and while the bimolecular form could be distin- 



^ Atti R. Accad. Lincei (5), 6, 208 (1897). 

 1° Z. physi^ Chem., 36, 590 (1901). 

 ^^ Loc. cit. 



