Chapter III. 



The Conductance of Electrolytic Solutions in Various 



Solvents. 



1. Characteristic Forms of the Conductance-Concentration Curve. 

 The property of forming solutions which possess the power of con- 

 ducting the current is one not restricted to water. Nor, indeed, are 

 electrolytes in non-aqueous solvents restricted entirely to those sub- 

 stances which are electrolytes in aqueous solution. As the field of non- 

 aqueous solutions has been extended in recent years, it has become more 

 and more apparent that the property of forming solutions which conduct 

 the current is one which is common to a great many substances. Indeed, 

 it seems not improbable that all liquid non-metallic media yield elec- 

 trolytic solutions when suitable substances are dissolved in them. 



In attempting to account for the properties of electrolytic solutions in 

 water, it is difficult to distinguish between those properties which are 

 characteristic of electrolytic solutions in general and those which are 

 characteristic of aqueous 'solutions alone. Such a knowledge can be 

 obtained only from a study of the properties of electrolytic solutions in a 

 large variety of solvents, and it appears unlikely that the properties of 

 electrolytic solutions may be successfully accounted for until we possess 

 reliable data as to the properties of non-aqueous solutions. While this 

 field has been greatly extended during the past two decades, it is only in 

 the case of a few solvents that we possess a sufficient mass of facts to 

 enable us to treat the subject with a measurable degree of completeness. 



From a constitutional point of view, the alcohols are more nearly 

 related to water than are any other solvents, since they may be looked 

 upon as water in which one of the hydrogen atoms has been substituted 

 by a hydrocarbon group. We should expect the properties of these 

 solvents to diverge progressively from those of water as the size and 

 complexity of the hydrocarbon group increases, and such has indeed been 

 found to be the case. In general, the ionizing power of the alcohols 

 diminishes as the complexity of the carbon group increases. Accord- 

 ingly, methyl alcohol stands much nearer to water than do any of the 

 other representatives of this class of solvents. 



For the purposes of illustration we may consider the conductance of 



46 



