THE CONDUCTANCE OF SOLUTIONS VISCOSITIES 



119 



at sufficiently high concentrations, the conductance curve ultimately falls, 

 and falls the more rapidly the higher the concentration. There appears 

 to be no exception to this behavior. There can be little question but 

 that the final decrease in the conductance is due to a large increase in the 

 viscosity of the medium. This is illustrated in Figure 20, where the 

 conductance of solutions of silver nitrate in methylamine 13 is repre- 

 sented as a function of the concentration. The maximum lies a little 



19* 



160 



128 







1" 





0.96 



' 

 



- 



i.i 



0.8 



I/>K (concentration). 



FIG. 19. Showing the Influence of Fluidity Change on the Conductance of Solutions 



of KI inNHaat 33.5. 



above normal concentration at 33 and is displaced toward higher 

 concentrations at higher temperatures. 



3. Relation between Viscosity and Conductance on the Addition of 

 Non-Electrolytes. The addition of a non-electrolyte to a solution of an 

 electrolyte in most cases increases the viscosity of the solution. 1 * The 

 conductance change on the addition of a non-electrolyte is in the same 

 direction as that of the viscosity change, but in most cases the con- 

 ductance change is smaller than the corresponding viscosity change. 



Fitzgerald, Joe. cit., p. 640. 



14 In a few instances, however, where the added non-electrolyte forma a stable complex 

 with one of the ions in solution, the addition of a non-electrolyte results in a viscosity 

 decrease. An example of this effect is found in solutions of certain of the heavy metals 

 in water whose viscosity is reduced on the addition of ammonia. [Blanchard, J. Am. 

 Chem. Soc. 26, 1315 (1904).] In these cases the addition of a non-electrolyte causes a 

 decrease in the viscosity only so long as it combines with the electrolyte to form the 

 complex. Beyond this point the viscosity in general increases with further addition of 

 non-electrolyte. 



