A short manual of analytical chemistry, qualitative and quantitative,--inorganic and organic . s—insoluble in excess. (b) DRY REACTION. (To be practised on cadmium carbonate—CdCOs.) Heated on charcoal before the blowpipe, a brownish incrustation of oxideis produced, owing to reduction of the metal and its subsequent volatilisationand oxidation by the outer flame. DIVISION B. Metals which are precipitated by sulphuretted hydro^n in the presence ofhydrochloric acid, but yield sulphides which are soluble in ammonium sulphide. I. AESENIC (As).id) WET REACTIONS. (To be practised with a solution of
A short manual of analytical chemistry, qualitative and quantitative,--inorganic and organic . s—insoluble in excess. (b) DRY REACTION. (To be practised on cadmium carbonate—CdCOs.) Heated on charcoal before the blowpipe, a brownish incrustation of oxideis produced, owing to reduction of the metal and its subsequent volatilisationand oxidation by the outer flame. DIVISION B. Metals which are precipitated by sulphuretted hydro^n in the presence ofhydrochloric acid, but yield sulphides which are soluble in ammonium sulphide. I. AESENIC (As).id) WET REACTIONS. (To be practised with a solution of arsenious anhydride in boiling waterslightly acidulated by hydrochloric acid.)I. HjS, after acidulation with HCl, causes a yellow precipitate of arsenioussulphide—As^Ss—soluble in ammonium sulphide, forming ammoniumsulpharsenite—(NHi)3AsSg—but insoluble in strong boiling hydro-chloric acid (distinction from the sulphides of Sb and Sn). Thisprecipitate is also soluble in cold solution of commercial carbonate ofammonia (distinction from the sulphides of Sb, Sn, Au, and Pt). Dried. 16 DETECTION OF THE METALS. and heated in a small tube with a mixture of NajCOj and KCy, ityields a mirror of arsenic. (Detects i part of As in 8,000.) 2. Boiled with KHO and a fragment o/Ziac, arseniuretted hydrogen—AsHj— is evolved, which stains black a paper moistened with solution ofargentic nitrate and held over the mouth of the tube during the ebul-lition (Fleitmanns test). 3. Boiled with \ of its bulk of HCl and a slip of Copper, a grey coating is deposited on the copper of cupric arsenide. On drying the coppercarefully, cutting it into fragments, and heating in a wide tube, acrystalline sublimate of arsenious anhydride—^AsjOs—is obtained, which, when examined by a lens, is seen tobe in octohedral crystals, and, when dissolved in water,gives a yellow precipitate of argentic arsenite—AgjAsOj—with solution of ammonio-nitrate of silver (ReincKstest). (Detects i part As in 40,
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Keywords: ., bo, bookcentury1800, bookdecade1890, booksubjectchemistryanalytic
