428 



Dr. Divers on Salts of Nitrous Oxide. [Apr. 20, 



the alkalinity of the solution to test-paper, and its capability of being pre- 

 cipitated by many metallic salts. 



7. The following reactions having as yet been only observed with a 

 solution thus obtained, it is possible that some of them may not be due 

 simply to the new acid : — 



Barium chloride gives no precipitate. 



Lead acetate gives a cream-white flocculent precipitate, which generally, 

 on standing, changes to a very dense, full yellow precipitate. This pre- 

 cipitate is unchanged by boiling in water or in its mother liquor, is soluble 

 in acetic and other acids, slowly, if at all, affected by ammonia or sodium 

 carbonate, and instantly decomposed by caustic soda. 



Mercuric chloride gives a cream-white flocculent precipitate. 



Mercurous nitrate gives a blackish-grey precipitate, not improbably a 

 mixture of mercury and the mercuric salt. 



Cupric sulphate, a yellowish olive-green flocculent precipitate, soluble 

 in acids and ammonia, insoluble in caustic soda, and unaffected by boiling 

 in water or its mother liquor. The colour of this precipitate closely re- 

 sembles the colour of a copper-salt mixed with a nitrite. 



Zinc chloride gives a white precipitate. 



Manganese chloride gives a whitish precipitate. 



Nickel chloride gives a greenish, almost white precipitate. 



Cobalt nitrate gives no precipitate (?). 



Alum gives a white precipitate. 



Ferric chloride gives a slight reddish-brown precipitate. 



Ferrous sulphate gives a whitish precipitate, instantly darkening to 

 dirty blackish green and eventually reddish brown. On addition of ferric 

 chloride effervescence slowly commences ; and with ferrous sulphate the 

 same thing happens, but still more slowly. It is very probable that the 

 iron and aluminium precipitates are simply hydrates ; and if so, the action 

 of this salt in these cases closely resembles that of a carbonate. 



Silver nitrate behaves as already described. 



Sodium chloride gives an alkaline solution with the silver-salt, which is 

 changed to chloride. 



Ammonium chloride gives the same result as sodium chloride, but the 

 solution at once evolves ammonia. The existence, therefore, of the am- 

 monium salt of the new acid is problematical. 



Potassium permanganate gives the beautiful changes of colour from its 

 own violet, through purple, blue, and chrome-green, to manganate green, 

 and then a brown precipitate. The exhibition of this series of colours is 

 more certain in the presence of a little caustic alkali. In this reaction the 

 new salt resembles a nitrite, but it is much more sensitive than this. 



Potassium iodide gives no reaction ; it does with nitrite. 



Iodine solution is decolorized immediately ; so that if a nitrite, not in 

 excess, is added to a solution of the new salt, the addition of starch and 

 potassium iodide produces no coloration. 



