Potash Yellow Mercurial

Yellow mercury(ll) oxide is precipitated upon the addition of excess caustic soda or caustic potash to an aqueous solution of mercury(ll) nitrate or chloride ... 

Tests for the Salts of Mercury. The salts of mercury are all volatilised at a dull red heat—give a white precipitate with prussiate of potash, a black one with sulphuretted hydrogen and hydrosulphurets, an orange-yellow one with gallio acid, and with a plate of polished copper, a white coat of metallic mercurr. 

Characters and Tests.—Opaque white powder, on which cold water, alcohol, and ether have no action. Digested with caustic potash, it evolves ammonia and acquires a pale yellow colour (mercuric oxide). The clear liquid obtained by Altering this mixture, after being acidulated with nitric acid, gives a white precipitate (silver chloride) with silver nitrate. Boiled with stannous chloride, it becomes grey and afibrds globules of metallic mercury. Entirely volatilizes at a heat under redness. 

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