Licence: Public Domain Mark
Credit: Qualitative chemical analysis / by C. Remigius Fresenius. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![IlYDROCIILOrvIDE OF PLATINUM. 7a § 71. 8. stannous Chloride or Protochloride of Tin, SnCl [SnCg. Crystallized, SnCl + 2aq [SnCL,2H,0]. I'reparation.—Gmin tin is reduced to powder by means of a file, or 1)V fusing it in a small porcelain dish, removing it from the fire, and trituratino- with a pestle until the tin again becomes solid.* The granulated or powdered tin is boiled for some time with concentrated hydrochloric acid in a flask (taking care always to have an excess pf tm in the vessel) until the evolution of hydrogen ceases almost entirely the solution is then diluted with 4 times the quantity of water shghtly acidified with hydrochloric acid, and filtered. The filtrate is kept for- use in a well-stoppered bottle containing some small pieces of granulated tin, or some pui-e tin-foil. If these precautions are neglected, the proto- chloride will soon change to bichloride, with separation of white oxy- chloride of tin, and the reagent will be \mfit for use. Tests.—When solution of stannous chloride is added to excess of solution of chloride of mercury, it should immediately produce a white' precipitate of mercurous chloride; when treated with sulphuretted hydrogen, it should give a dark brown precipitate; it should not be precipitated or rendered turbid by sulphuric acid. If the stannous, chloride solution is heated with 10 times its volume of pure fuming hydrochloric acid, it should not turn brown (arsenic). Vses.—The great tendency of stannous chloride to absorb oxygen,, and thus to form binoxide, or rather stannic chloride—as the binoxide in the moment of its formation reacts with the free hydrochloric acid present—makes this substance a most powerful reducing agent. It is more particularly suited to remove the part or the whole of the chlorine from chlorides. It is employed in the course of analysis as a test for- mercury; also for the detection of gold. § 72. 9. Hydrochloride of Platinum, HCl,PtCl, [H,PtC!„]. Crystallized, HCl,PtCl2 + 6aq [H,PtCI„,6H,0]. Prejjaration.—Platinum cHppings, purified by boiling with nitric acid, are treated with concentrated hydrochloric acid and some nitric acid in a narrow-necked flask, applying a very gentle heat, and adding fresh portions of nitric acid occasionally, until the platinum is entirely dissolved. The solution is evaporated on the water-bath, with addition- of hydrochloric acid, and the semifluid residue dissolved in 10 parts of water for use. Tests.—Chloride of platinum, when evaporated to dryness in the water- bath, should leave a residue which dissolves completely in spirit of wine. Uses.—Chloride of platinum forms very spai-ingly soluble double salts with chloride of potassium and chloride of ammonium, but not with chloride of sodium ; it serves therefore to detect ammonia and potassa, and may, indeed, be looked upon as the most delicate I'eagent for the latter substance in the wet way. * It is far more convenient to use graniilcatecl tin, whicli may be readily ob- tained by melting the metal in a crucible or dish, and pouring it into a basin of ■water from the height of a foot or so.—[Editor.]](https://iiif.wellcomecollection.org/image/b21966953_0097.jp2/full/800%2C/0/default.jpg)
