36 MORRIS LOEB 



consider the strongest. Indeed, according to Arrhenius, 

 chemical activity depends upon the degree of electrolytic dis- 

 sociation, only the dissociated molecules being capable of 

 entering into reaction. A fundamental difference is hereby 

 inferred to exist between reactions among electrolytes and 

 reactions introducing only non-electrolytes, or, to recall 

 antiquated notions, between reactions which involve sub- 

 stances of the water and hydrochloric acid types, and those 

 involving merely the hydrogen and ammonia types. Valid 

 objections raised to this distinction would upset the theory 

 from the chemist's standpoint: examples in favor of the dis- 

 tinction have been adduced, such as the fact that the char- 

 acteristic halogen reaction with silver nitrate is only shown 

 by such compounds in which the halogen can be supposed to 

 exist as a free ion, while with those which contain the halo- 

 gen within the radicle, like trichloracetic acid, the reaction 

 fails. Considering by themselves the reactions between 

 electrolytes, it is noticeable that the presence of water or 

 another solvent appears to be necessary (cf . the passivity of 

 absolutely dry gases). The law of Guldberg and Waage must 

 be modified in so far that the speed of reaction is not a func- 

 tion of the total masses of the electrolytes in solution, but 

 of the masses of dissociated ions : van 't Hoff has introduced 

 the coefficient i (isotonic coefficient) successfully enough into 

 these considerations, and i has already been shown to be a 

 function of a (II). In the acceleration or retardation of 

 etherification and saponification, the acids and bases must 

 act proportionately to their stages of dissociation, so that 

 Ostwald's old affinity-coefficients must correspond with the 

 values of k in equation III, which is also found to be true; 

 for the same reason the effectiveness of weaker acids (non- 

 dissociated) increases more rapidly for additional dilution 

 than does that of stronger acids which are much nearer their 



