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Tests for the Presence of Ar- solution

With the bases this acid forms senic Acid. Sulphuretted hydrogen gives CHROMATES. Chromate of lead forms the a yellow precipitate; nitrate of silver added pigment known as chrome-yellow. to the solution of an arseniate gives a pre- 3946. Το Obtain Chromic Acid. Take cipitate of a brick red color; nitrate of lead 10 measures of a saturated cold solution of gives a white one, and the salts of copper a bichromate of potassa, mix with it 15 meabluish colored onc. Pure lump sugar dis- sures sulphuric acid, and allow the mixture to solved in an aqueous solution of arsenic acid, cool. The chromic acid is deposited in crys-/ becomes in a few hours of a reddish color, and tals, which, after decanting the mother liquid, afterwards of a magnificent purple. For some test purposes it will be advisable to add sulphurous acid to the suspected liquor, and boil it for a short time, when the arsenic acid will be reduced to arsenious acid, in which state it will be susceptible of more delicate tests. (Sec No. 3037.) are placed on a tile to drain, covered with a bell glass.