Coloured analytical tables : showing the behaviour of the more common metals and acids to the ordinary reagents, with special reference to the colour of the various oxides, salts, precipitates, flames, borax-beads, and blowpipe reactions a class-book for students in hospitals, colleges and schools / by H. Wilson Hake.

  • Hake, H. Wilson (Henry Wilson), 1857-1930
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Coloured analytical tables : showing the behaviour of the more common metals and acids to the ordinary reagents, with special reference to the colour of the various oxides, salts, precipitates, flames, borax-beads, and blowpipe reactions a class-book for students in hospitals, colleges and schools / by H. Wilson Hake. Source: Wellcome Collection.

    34/40 (page 4)
    To a fresh solution add, B. Silver nitrate, a precipitate indicates: — 1. Chlorides.—Cl; white precipitate (AgCl), soluble in ammonia, in- soluble in nitric acid ; the prccipitato fuses on heating. N.B.—Solid chlorides yield colourless pungent fumes (HC1) when treated with strong sulphuric acid, which render a drop of silver nitrate, on the end of a glass rod, milky; or when heated with strong sulphuric acid and dioxide of manganese (Mn02) yield chlorine gas (green when in quantity), which bleaches moist litmus paper. Insoluble chlorides. These are PbCl2, AgCl, and Hg2Cl2. They are easily recognized by their behaviour to ammonia (see Table I.) ; the last is soluble in aqua regia, and is then converted into mer- curic chloride, HgCl2 (see Table IV.). 2. Cyanides.—CN ; white precipitate (AgCN), soluble in strong am- monia and in strong boiling nitric acid ; the precipitate yields metallic silver on heating, and evolves prussic acid when warmed with dilute hydrochloric acid (see below). N.B.—Solutions of cyanides yield poisonous vapours of hydro- cyanic acid (prussic acid, IICN) on heating with dilute hydro- chloric acid; the vapours have an odour of bitter almonds; and if boiled with ferrous sulphate (FeS04) and a very little ferric chloride (Fe2Cl8) and excess of potash (KIIO), and, finally, made acid with hydrochloric acid, yield insoluble Prussian blue (Fe.Cyltj). Insoluble cyanides. Most of the cyanides, except those of the alkalies and mercury, are insoluble; but most yield prussic acid as above. 3. Bromides.—Br ; pale yellow precipitate (AgBr), soluble in ammonia with difficulty ; insoluble in nitric acid. The precipitate or any solid bromide yields red-brown pungent vapours of bromine with strong sulphuric acid, which colour starch-paste orange. 4. Iodides.—I; pale yellow (Agl), insoluble in, but whitened by, am- monia, insoluble in nitric acid ; the precipitate or any solid iodide yields violet vapours of iodine with strong sulphuric acid, which colour starch-paste blue. C. Test specially for the following inorganic acids :— 1. Nitrates.—N03. N.B.—All nitrates (except a few basic nitrates) are soluble in water. Solid nitrates yield (1) colourless pungent fumes (IINO;J) with strong sulphuric acid, which do not affect silver nitrate, and (2) red fumes, with strong sulphuric acid and metallic copper. A solution of a nitrate, mixed with a solution of ferrous sulphate, yields, in the cold, an amethyst or brown ring at the point of junc- tion with strong sulphuric acid, when carefully poured on to it so as to form an upper layer. 2. Sulphides.—S. In solution or solid, sulphides yield sulphuretted hydrogen (SIX..) on heating with dilute sulphuric or strong hydro- chloric acid. The gas may be detected by its smell and by its blackening paper moistened with lead acetate [Pb(C2H302)2]. Solid sulphides placed cn a bright silver coin render it black after moistening with dilute sulphuric acid.