ELECTROLYTES IN MIXED SOLVENTS 185 



TABLE LXXIII. 



CONDUCTANCE OF 0.2 N TRICHLOROBUTYRIC ACID IN CH 3 OH IN THE 

 PRESENCE OF WATER. 



10 2.0 



A 0.446 0.825 1.283 



In a 0.2 normal solution of this acid the conductance is increased 100 

 per cent on the addition of one mol of water. In other words, the ioniza- 

 tion is increased somewhat over 100 per cent by this addition of water. 

 In this respect the acids behave in a manner similar to that of typical 

 salts which have a great tendency to form hydrates. 



The effect of water on the ionization of the weaker acids is clearly 

 shown in the increased value of the ionization constants of these acids 

 on addition of water. In Table LXXIV are given values of the ioniza- 

 tion constant 12 for trichloroacetic acid in absolute alcohol and in alcohol 

 containing 0.622 mols of water at different dilutions. Excepting at the 

 highest concentrations, the constant varies but little with the concentra- 

 tion of the acid. 



TABLE LXXIV. 



IONIZATION CONSTANT OF TRICHLOROACETIC ACID IN ALCOHOL IN THE 

 ABSENCE AND IN THE PRESENCE OF WATER. 



K X 10- 6 

 V Pure Alcohol C R Q = 0.622 N 



5.5 5.03 31.1 



11. 4.74 29.3 



22. 4.45 28.6 



44. 4.45 27.6 



88. 4.50 27.6 



176. 28.4 



It is evident that, due to the addition of 0.622 mols of water, the 

 ionization constant of trichloroacetic acid is increased approximately six 

 times. Corresponding to this increase in the value of the ionization con- 

 stant of the acid, the conductance of the acid is obviously greatly 

 increased. The effect of water on the conductance of different electro- 

 lytes is shown in Figure 41. The great percentage increase in the con- 

 ductance of trichloroacetic acid will be noted in contrast to a smaller 

 increase in the case of picric acid and lithium chloride and a large decrease 

 in that of hydrochloric acid. 



"Braune, Ztschr. f. phys. Chem. 85, 170 (1913). 



