THE USE OF LIQUID AMMONIA AS A SOLVENT 121 



iodide in concentrated solutions are very high, but the reverse 

 is the case with potassium nitrate, ammonium chloride and 

 silver iodide. In ammonia solution the anions appear to exert 

 a greater influence on the ionisation than the kations, the iodides 

 being the most highly ionised of the salts examined, the bromides 

 and chlorides following in the order named. In all cases it 

 was found that the ionisation was far less than in water — 

 potassium nitrate, for example, in a third normal solution being 

 one-fourth ionised, while in water, at the same concentration, 

 it is three-quarters ionised. Even at a dilution of a thousandth 

 normal in ammonia solution the salt is less than three-quarters 

 ionised, but in water the ionisation is practically complete. 

 The cyanides of the heavy metals and cyanacetamide are 

 remarkable in showing a decrease in the molecular conductivity 

 with increasing dilution in the more concentrated solutions. 

 As the dilution increases the molecular conductivity passes 

 through a minimum and then increases with the dilution in 

 the normal manner. 



The results obtained with the acid amides are of great 

 interest and justify the use of the term " ammono-acids." The 

 analogy between the acid amides and ammonia on the one 

 hand and the oxygen acids and water on the other was found 

 to extend to the conductivity of the solutions of the acid amides 

 in ammonia. The amides of the weaker acids yielded solutions 

 which were poor conductors, whilst the amides of the stronger 

 acids were found to conduct very well. For example, urea — 

 the amide of the weak carbonic acid — scarcely conducts at all, 

 acetamide and benzamide form poorly conducting solutions, 

 formamide and cyanacetamide conduct much better, whilst the 

 amides of the strong sulphonic acids, as well as picramide 

 (trinitro-aniline), nitramide and sulphamide are excellent con- 

 ductors. Of the metallic salts of the acid amides (ammono-salts) 

 mercury succinimide was the only one of which the conductivity 

 was measured. It gives a good conducting solution. 



Many of the nitro-compounds, both aliphatic and aromatic, 

 give solutions which are excellent conductors, many of these 

 solutions being strongly coloured. 



Measurements of electric potential in liquid ammonia have 

 been made by Wilsmore (24), Johnson and Wilsmore (25), and 

 Cady (26); the effect of dissolved substances on the boiling-point 

 of ammonia has been studied by Franklin and Kraus (27). 



