HETEROGENEOUS EQUILIBRIA 233 



however, that at lower concentrations the curves for the three salts ap- 

 proach that of an ideal system, assuming the ionization to be given by 



the conductance ratio -T-. 



Ao 



More recently the methods for determining the temperature of solu- 

 tions in equilibrium with ice have been greatly refined, and molecular 

 weight determinations are available at very low concentrations. In 

 Table LXXXVI, under ^ are given values of the ionization for potassium 



chloride at low concentrations as determined by Adams 3 and by Bed- 

 ford. 4 Under y c are given values of the ionization at the same concen- 

 trations as determined from conductance measurements. 



TABLE LXXXVI. 



COMPARISON OF THE IONIZATION VALUES FOR POTASSIUM CHLORIDE FROM 

 FREEZING POINT AND CONDUCTANCE MEASUREMENTS. 



C X 10 3 Yi (Adams) y^ (Bedford) y c 



2 0.969 .... 0.971 



5 0.961 0.959 0.956 



10 0.943 0.939 0.941 



20 0.922 0.915 0.922 



50 0.888 .... 0.889 



100 0.861 .... 0.860 



An examination of this table shows that the ionization values as deter- 

 mined by the freezing point method correspond within the limits of error 

 with those as determined by the conductance method. The temperature of 

 the conductance measurements, in this case, was 18, while that of the 

 freezing point measurements was necessarily in the neighborhood of 0. 

 It is known, however, that at fairly high dilutions the ionization of salts 

 varies only little between .0 and 18. The results are therefore com- 

 parable. 



In Table LXXXVII are given values of the ionization as determined 

 from freezing point and conductance measurements for solutions of potas- 

 sium nitrate, potassium iodate, sodium iodate, and for equi-molar mix- 

 tures of potassium chloride and potassium nitrate, and potassium iodate 

 and sodium iodate. 5 



Examining the results given in the following table, it is evident that, 

 in the case of potassium nitrate, the ionization values by the two methods 



Adams, J. Am. Chem. Soc. 37, 482 (1915). 



* Bedford, Proc. Roy. Soc. (A) 83, 454 (1910). 



Hall and Harkins, J. Am. Chem. Soc. S8, 2658 (1916). 



