154 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



slum chloride and 1.1 for nitric acid. ' It is evident that at the higher 

 temperatures the strong acids and bases are relatively much weaker 

 than at lower temperatures. 



Owing to uncertainties in the conductance values and the meagreness 

 of the experimental material at the higher temperatures, it is not possible 

 to determine whether or not the mass-action law actually is approached 

 as a limiting form in the case of aqueous solutions; but it seems not 

 unlikely that such is the case. In view of the high value of the ioniza- 

 tion constant of water and the relatively low value of the ionization 

 function of the acids and bases at higher temperatures, it follows that at 

 these temperatures typical salts will be hydrolyzed to an appreciable 

 extent in dilute solutions and that salts of slightly weaker acids and 

 bases, and particularly of the polybasic acids and the polyacid bases, 

 undergo appreciable hydrolysis. 



3. The Conductance of Solutions in N on- Aqueous Solvents as a 

 Function of the Temperature. In aqueous solutions, the maxima of the 

 temperature-conductance curves lie at temperatures which are the lower 

 the higher the concentration of the solution. The observed conductance 

 change with rising temperature is the resultant effect of an increase in 

 conductance due to increasing fluidity of the solvent, and a decrease, 

 due to decreasing ionization of the salt. In very dilute solutions, where 

 the ionization is approaching unity in all cases, the conductance in- 

 creases with the temperature at all temperatures, since the ionization 

 remains practically fixed in the neighborhood of unity, while the fluidity 

 of the solvent increases. At higher concentrations, the ionization de- 

 creases with the temperature and presumably, at sufficiently high tem- 

 peratures, it decreases at a sufficient rate to overcome the increase in 

 conductance due to the fluidity change of the solvent. When the two 

 effects balance, the temperature coefficient becomes ze^p, while at higher 

 concentrations the temperature coefficient becomes negative. 



In non-aqueous solutions, particularly in solvents of low dielectric 

 constant, the temperature-conductance curves, as functions of the con- 

 centration, have a somewhat different form. In very dilute solutions, 

 where the ionization is great, the conductance increases with the tem- 

 perature because of the increasing fluidity of the solvent. At certain 

 intermediate concentrations and above certain temperatures, the con- 

 ductance decreases with the temperature, although at much lower tem- 

 peratures the curve in general passes through a maximum. At much 

 higher concentrations, that is, in the neighborhood of normal and above, 

 the temperature coefficient is again throughout positive; that is, the 

 conductance increases with the temperature at all temperatures. In the 



