SODIUM OE. POTASSIUM : EDWARD DIVERS. 45 



evolves heat in dissolving in water, and is insoluble in alcohol. 

 It only slowly takes water from a solution of itself. Heated 

 in a closely covered vessel it yields nitrogen and sodium oxide 

 mixed with some nitrite :— 3(NaON), =2^2 + 2Na,0 + 2NaNO,. The 

 salt bears a heat of 300° without decomposing, and then melts 

 and effervesces ; glass, platinum, and even silver are freely 

 attacked by the fused mass. The mass hisses when water is 

 added to it. Sodium hydroxide and nitrite are the solid pro- 

 ducts when the hydrated salt is quickly heated, and nitrous 

 oxide, as well as nitrogen, is given off. Strong sulphuric acid 

 decomposes the salt, with production of odourless white vapours 

 and does not form nitrosyl sulphate, when the sodium salt is 

 pure enough. 



The salt or a fairly concentrated solution of it effervesces 

 with a dilute acid like a carbonate. The solution precipitates 

 calcuim and most other hyponitrites at once from the respective 

 reagents. It dissolves a little silver hyponitrite and decomposes 

 silver chloride (see the account of silver hyponitrite, p. 50). 

 Dry sodium hyponitrite is not decomposed by carbon dioxide 

 and, since the hydrated or dissolved salt partly decomposes by 

 interaction with the water, its power of fixing carbon dioxide 

 does not indicate that it is directly decomposaljle by that sub- 

 stance. The solution decomposes moderately fast, when boiled, 

 into hydroxide and nitrous oxide. Allowed to stand for a day 

 it developes in itself a trace of nitrite. 



Potassium hyponitrite ; potassium amalgam. 



The preparation of a solution of potassium hyponitrite is 

 throughout like that of a solution of the sodium salt. It is 



