174 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



TABLE LXIII. 



CONDUCTANCE OF KI IN CH 3 OH AS A FUNCTION OF THE DENSITY 

 OF THE SOLVENT. 



Density \i X 10 6 



of Solvent 245 250 



0.251 45.6 37.2 



0.220 28.8 22.6 



0.208 21.2 . 16.83 



0.178 8.0 6.0 



0.163 3.7 2.8 



0.127 1.44 1.2 



from 1.44 to 45.6, or approximately 50 times. At 250 the increase in 

 the conductance is not so great, since for the same concentration change 

 the conductance increases only from 1.2 to 37.2, or 30 times. The 

 A, ^-curves indicate a fairly rapid decrease in the conductance immedi- 

 ately above the critical temperature. As the temperature rises these 

 curves appear to approach a horizontal straight line. The lower the 

 concentration, the less does the conductance change with the temperature. 



At a given temperature, the addition of a given amount of solvent 

 increases the conductance the more the greater the density of the solvent. 

 In other words, the A,C-curves at constant temperature are strongly 

 convex toward the axis of concentrations. 



It is to be borne in mind that the conductance of a solution is a 

 function of the number of carriers and the speed with which these car- 

 riers move. Unless the nature of the carriers changes very greatly, we 

 should expect that the speed of the carriers would be the greater the 

 lower the density of the solvent, since the viscosity of a gas increases 

 with its density. Since, now, the conductance of a solution increases 

 very rapidly with the density and since this increase is the greater the 

 greater the density of the solvent, it is difficult to escape the conclusion 

 that the increase in the conductance of these solutions is due to an 

 increase in the number of carriers present in them. 



According to the commonly accepted theory of electrolytic solutions, 

 the change in the conductance of solutions as a function of the concen- 

 tration is due to a change in the relative number of carriers; that is, 

 to a change in the ionization of the electrolyte. Because of various 

 difficulties which have arisen in accounting for the properties of strong 

 electrolytes, some writers have suggested that strong electrolytes in 

 solution are completely ionized. The study of the properties of non- 

 aqueous solutions and of solutions at higher temperatures yields no 

 apparent support for such an hypothesis. If the salts in solvents of low 



