52 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



It is evident that, in order to account for the phenomena of electro- 

 lytic solutions, it is necessary to take into consideration the fact that 

 the form of the conductance curve as observed in water is not a general 

 type, but is only one extreme of several types. Any comprehensive 

 theory of electrolytic solutions must obviously account for both types. 



The only non-aqueous solvent with regard to whose solutions we have 

 anything like complete information at the present time is liquid ammonia. 

 This solvent yields electrolytic solutions with an extremely large variety 

 of substances and we shall have frequent occasion to refer to these 

 solutions below. At this point it will be sufficient to give an example of 

 the conductance curve for a typical salt dissolved in liquid ammonia. 

 In Table XVIII 8 are given values of the conductance of solutions of 

 potassium nitrate in liquid ammonia at its boiling point, approximately 

 33, at a series of dilutions. It is evident that these solutions belong 

 to the aqueous type, the conductance increasing throughout with decreas- 

 ing concentration and approaching a limiting value at very low concen- 

 trations. The limiting value for potassium nitrate is 339. 9 



TABLE XVIII. 

 CONDUCTANCE OF KN0 3 IN NH 3 AT 33. 



V 324 1001 2514 6162 23060 69820 oo 



A 192.7 245.0 282.7 309.9 330.1 338.6 339. 



Y 0.567 0.720 0.831 0.912 0.972 0.995 



Solutions of typical salts in liquid ammonia exhibit a somewhat higher 

 conductance than do the corresponding salts in water, but it is evident 

 that the ionization of these salts in liquid ammonia solutions is consid- 

 erably lower than in water, as may be seen from Figure 3. Ammonia 

 apparently approaches ordinary alcohol and acetone in its ionizing power. 

 In the case of certain solutions in liquid ammonia, an intermediate type 

 of conductance curve is found. This is the case, for example, with potas- 

 sium amide whose curve exhibits a minimum. 10 



A similar, but in some respects a slightly different, case is found in 

 certain of the cyanides, of which mercuric cyanide and silver cyanide 

 may serve as examples. The conductance values for solutions of mer- 

 curic cyanide in ammonia are given in Table XIX. 11 



Franklin and Kraus, Am. Chem. J. 23, 277 (1900). 



9 Kraus and Bray, J. Am. Chem. Soc. 35, 1037 (1913). 



10 Franklin, Ztachr. f. phj/s. Chem. 69, 290 (1909). 

 "Franklin and Kraus, loc. cit. 



