SOLUTIONS AS A FUNCTION OF TEMPERATURE 155 



following table are given values of the conductance of potassium iodide 

 and ammonium sulphocyanate in S0 2 at temperatures from 33 to 

 + 10. 12 



TABLE LVI. 



CONDUCTANCE OF ELECTROLYTES IN S0 2 AT DIFFERENT TEMPERATURES. 



Potassium Iodide. 

 V 33 20 10 +10 



1.00 37.7 44.1 46.9 51.2 54.5 



128.0 65.9 66.9 66.5 64.5 62.0 

 4000. 139.0 151.0 162.5 166.3 168.7 



Ammonium Sulphocyanate. 



1.28 9.42 10.17 10.82 11.13 11.33 



167.1 17.01 16.44 15.92 15.10 14.01 



It will be observed that in the neighborhood of normal the con- 

 ductance curve for both salts rises throughout with increasing tempera- 

 ture. In the neighborhood of 0.01 normal there is a slight increase 

 between 33 and 20 in the case of potassium iodide, after which 

 the conductance decreases throughout with the temperature. At the 

 lo'wer concentration, the conductance of ammonium sulphocyanate de- 

 creases throughout with increasing temperature. At a dilution of four 

 thousand liters, the conductance of potassium iodide increases throughout 

 with increasing temperature. 



The effect of temperature on the conductance of solutions in non- 

 aqueous solvents is readily interpreted in terms of Equation 11. What 

 we have to consider is the influence of temperature upon the constants 

 of this equation. We have seen that as the dielectric constant of the 

 solvent decreases, Ce., as the temperature rises, the value of the constant 

 K decreases and ultimately reaches very low values. On the other hand, 

 as the dielectric constant decreases, the exponent m increases while the 

 constant D remains practically independent of the dielectric constant of 

 the solvent. If the mass-action constant K is not too small, then, at high 

 dilutions, the ionization of the electrolyte will approach unity, whatever 

 the dielectric constant of the solvent. It follows, therefore, that with 

 increasing temperature the conductance of such dilute solutions will 

 increase throughout as the temperature increases. The constant D, as 

 we have seen, determines the value of the ionization at very high con- 

 centrations. At unit ion concentration the value of the ionization is 



"Franklin, J. PJiys. Chem. 15, 675 (1911). 



