Notes on analytical chemistry : for students in medicine / by Albert J. Bernays.
- Albert Bernays
- Date:
- 1886
Licence: Public Domain Mark
Credit: Notes on analytical chemistry : for students in medicine / by Albert J. Bernays. Source: Wellcome Collection.
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![Arsenic, antimony, mercury, lead, copj^er, and silver are pre- cipitated by hydrochloric acid (Group-test I., mercurous, lead or silver) or by hydrochloric acid and hydrogen sulphide (Group- test II., arsenic, antimony, mercuric, lead or cop])er). The precipitates tiltered, and washed with solution of hydrogen sulphide, will most probably be of sufficiently characteristic color to recognize. Lead suli)hide and copper sulphide are easily dissolved by dilute nitric acid as nitrates : mercuric sulphide is not attacked. Zinc is precipitated by ammonium sulphide, and cannot bo mistaken if Group-tests I. and II. have given no reaction. The precipitated zinc sulphide can be washed on a filter, and calcined on platiniim. Yellow whilst hot, white when cold, would prove zinc oxide. Moistened with nitrate of cobalt, and re-heated, Einman's green would confirm zinc. Barium would not be precipitated by Group-test IV. Sodium carbonate would give a pr. with a barium salt, and the pr. after washing, dissolved in hydrochloric acid, could be examined as solution of barium chloride (p. 30). Of course, if lead or barium has been found, a sulphate need not be looked for. Antimonous chloride has a strongly acid reaction : tartar emetic is faintly acid. If an arsenite is present, the solution would be strongly alkaline. For further information, the Index must be consulted. FURTHER DIRECTIONS FOR THE DETECTION OF THE COMMON INSOLUBLE BODIES. Notice color and appearance. I. IF BLACK. Possibly cupric oxide, antimonous sulphide, manganese peroxide, ferrous sulphide, nickel, or cobalt sulphide, mercuric sulphide, bismuth sulphide, lead sulphide, cupric sul- phide, silver sulphide, carbon as graphite, carbon as charcoal. Boil at once the tincly-pounded substance with HCl. Cupric oxide, dissolves as green cupric chloride, precipitated black by iL8, and the sulphide when neutralized insoluble in (NHJ^S, (p. 21). On platinum no change. Heated with HCl a green and blue flame. ' Antimonous sulphide, dissolves as SbCl^, with evolution of H,,S. Orange-red sulphide precipitated by H.S, soluble, when neutralized, m (NH,),S (p. 18). Confirm H.S by lead-paper Manganese peroxide, dissolves in HCl as manganons chloride, with evolution of chlorine. Ignited on platinum changes to red-brown, and further heated with Na.,CO, gives a fused blue-green mass of manganate of sodium (pp. 27 and 46)](https://iiif.wellcomecollection.org/image/b21499056_0117.jp2/full/800%2C/0/default.jpg)
