ELECTROLYTIC DISSOCIATION 33 



theory would require. The coefficient i has been determined 

 for many electrolytes, both by the freezing-point method and 

 de Vries's and Hamburger's isotonism methods, and has in 

 almost every case been found to agree astonishingly well 

 with the corresponding value obtained from equation II, 

 after calculating a by equation I. The few exceptions are 

 found for salts which behave anomalously in other respects, 

 andfcan be explained by making further assumptions which 

 need not be discussed here. 



3. If k =2, that is if the electrolyte consists of but two 

 ions, as in the case of monobasic acids and their salts with 

 monovalent metals, the dissociation ought to obey the law 

 which has been found to hold for gaseous dissociation where 



one molecule breaks up into two constituents, = const., 



Pi 



p now referring to the osmotic pressure of the integral mole- 

 cules and pi to that of either set of ions of the dissociated 

 ones. The osmotic pressure depends upon the number of 

 molecules in the unit volume of solution. Therefore, if we 



call the volume of the solution V 9 p= , p\= l , and = 



V V n\ 



const. 



If the dissociation were complete, a result reached at in- 

 finite dilution, the molecular conductivity would reach a 

 maximum value /m>, but at the finite dilution F, it has a 

 smaller value p v9 which is a measure of the number of dis- 

 sociated molecules in the total. We can substitute in the 



last equation the value n\= and n=l-^- and obtain 



In this form the ratio has been examined by Ostwald, 

 and has been found to remain practically constant for any 



