60 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



ammonia are given in Table XXIII. 16 Here, again, we find a large varia- 

 tion in the value of the ionization constant for different electrolytes. 



TABLE XXIII. 

 VALUES OF K AND OF A FOR ORGANIC ELECTROLYTES IN NH 3 AT 33. 



Salt 10 4 # A 



Cyanacetamide 0.045 260 



Thiobenzamide 0.40 204 



Orthomethoxybenzenesulphonamide 0.40 208 



Paramethoxybenzenesulphonamide 0.50 208 



Nitromethane 0.53 278 



Sodiumnitromethane 0.78 278 



Benzenesulphonamide 1.39 208 



Metamethoxybenzenesulphonamide 1.81 208 



Orthonitrophenol 3.90 246 



Methylnitramine 8.4 256 



Phthalimide 8.7 248 



Benzoicsulphinide 12.0 206 



Metanitrobenzenesulphonamide 12.5 231 



Potassiummetanitrobenzenesulphonate 15.0 275 



Nitrourethaneammonium 21.6 262 



Trinitrobenzene 30.0 234 



Trinitraniline 30.0 234 



The strongest "of these, trinitraniline and trinitrobenzene, have ionization 

 constants as great, or greater, than those of typical salts in ammonia. 

 On the other hand, cyanacetamide has an ionization constant of only 

 0.045 X 10~ 4 . Cyanacetamide, therefore, is a weaker acid in ammonia 

 solution than acetic acid is in water, and of course a much weaker acid 

 than cyanacetic acid in water. In other respects, as regards the relation 

 of the ionization constants of these electrolytes to their constitution, we 

 find relations similar to those in aqueous solutions. The introduction of 

 strongly electronegative groups into the negative constituent increases 

 the value of the ionization constant. It will be observed that many of 

 the organic substances which act as electrolytes in ammonia solution are 

 not electrolytes in water. This is true of nearly all the acid amides and 

 of such compounds as trinitrobenzene. The positive ion, in the case of 

 the acid amides, as indeed in the case of all the acids in ammonia solu- 

 tion, is presumably the ammonium ion. 17 



Having seen that the mass-action law applies to dilute solutions of 

 practically all electrolytes in ammonia, we may inquire whether the same 



" Kraus and Bray, loc. cit. 

 Ibid., loc. cit., p. 1357. 



