SODIUM on POTASSIUM : EDWAED DIVERS. 61 



uitrite as had l)een reduced, thus getting hypouitrite and nitrite 

 together in solution in about equivalent proportions, in accord- 

 ance with tlie experience recorded in this paper. The precipita- 

 tion of silver hyponitrite was then proceeded with, in one 

 experiment, without previous neutralisation of sodium hydroxide, 

 and in another experiment only after neutralisation of the alkali. 

 'J'lie result was the same in the two experiments. There was 

 a bright yellow precipitate, not noticeably different from ordinary 

 hyponitrite, and the mother-liquor retained much alkali nitrite 

 or silver nitrite in the respective cases. The precipitate Avas 

 repeatedly washed with cold water, 1)ut the washing w^as stopped 

 when very little silver was being extracted. It proved to be 

 somewhat sensitive to light and heat. It was dried in the cold 

 and in a vacuum and then had its silver determined. This was 

 76.9 per cent. Nitrite could be easily detected in it, but the 

 compound, AgoNjO;., would have only 74 per cent, silver and 

 Ag^Np- only 76 per cent. Besides this, by prolonged washing 

 the hyponitrite can be made much purer. There is, therefore, 

 no evidence to be got from these experiments of the existence 

 of such a compound as Paal has described. 



Properties of a solution of hyponitrous acid. 



Solutions of hyponitrous acid are always prepared in one 

 way, that of decomposing silver hyponitrite w'itli just sufficient 

 dilute hydrochloric acid. Hyponitrous acid has been obtained 

 by Hantzsch and Kaufmann in crystals very deli^piescent and 

 unstable, by replacing water by dry ether in its preparation. 

 The acid in dilute solution reddens litmus not so strongly as 

 nitric acid but much more than carbonic acid. On drying the 



