SYSTEMS INTERMEDIATE 



ammonia, it has been definitely established that material effects accom- 

 pany the current through these solutions. The existence of such effects 

 is readily observed as a consequence of the characteristic color of these 

 solutions. If a current is passed between two platinum electrodes in 

 dilute solution of sodium or potassium in liquid ammonia, it is found 

 that the color in the immediate neighborhood of the cathode is intensi- 

 fied. This result is obviously due to the fact that, as the current passes 

 through the solution, the metallic element as an ion, either simple or 

 complex, is carried up to the cathode. The electrolytic character of the 



4" 







If 



94 



7.9 o-o 0.1 c.e 0.3 0.4 o.s o.e on 0,9 0.9 1.6 u i.i /.s 

 Log V. 



FIG. 63. Apparent Molecular Weight of Sodium in Liquid Ammonia at Different 



Concentrations. 



conduction process in dilute solutions of these metals in liquid ammonia 

 is therefore established; the metal is associated with the positive ion. 

 Taking into consideration the great tendency of the alkali metals to 

 act as positive ions, it is probable that in these solutions the metals are 

 present, in part at least, as charged atoms which do not differ from the 

 positive ions of salts of the same metals dissolved in the same solvent. 

 If positive ions are present in these solutions, then, obviously, nega- 

 tive ions must be present likewise. So far as may be observed, when a 

 current passes through a solution of a metal dissolved in liquid ammonia, 

 no material effect occurs at the anode, save that the concentration of 

 the metal in the immediate neighborhood of this electrode is diminished. 



