Chemical analysis, qualitative and quantitative / by Henry M. Noad ; with numerous additions by Campbell Morfit.

  • Henry Minchin Noad
Date:
1849
Catalogue details

Licence: Public Domain Mark

Credit: Chemical analysis, qualitative and quantitative / by Henry M. Noad ; with numerous additions by Campbell Morfit. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    most safely detected thus. Into the hydrochloric solution of the precipitate, diluted with water, a rod of metallic zinc is placed; the antimony and tin become thereby reduced, and are deposited in a pulverulent form on the zinc, from which they are easily removed. The finely divided metals are di- gested with nitric acid, and the oxides thus formed are heated with a hot saturated solution of bitartrate of potassa, or with a solution of tartaric acid. If complete solution take place, antimony alone is present, and may be confirmed by sulphur- etted hydrogen ; if a residue remain after a protracted diges- tion, it consists of peroxide of tin, the presence of which is confirmed by reduction before the blowpipe, with a mixture of cyanide of potassium and carbonate of soda on charcoal. B. 1, e. Special testing for Tin.—The remainder of the hydrochloric solution is evaporated to dryness, and the residue fused on charcoal, with a mixture of cyanide of potassium and carbonate of soda, before the reducing flame of the blow- pipe; no metallic globules make their appearance; absence of tin. The only metal present, therefore, of the sixth group, is platinum. B. 2. Examination of the portion insoluble in Sulphuret of Potassium.—It is boiled with nitric acid; it dissolves com- pletely with the exception of a light flocculent residue of sulphur; absence of mercury ; there may, however, be pre- sent all the metals of the fifth group, with the exception of silver. ]SjoTE.—Had a black residue remained insoluble, or but very sparingly soluble in nitric acid, it would have consisted of sulphuret of mercury; a small quantity of sulphate of lead may also have been present. To ascertain whether the mercury existed in the compound in the state of suboxide or as oxide, the black residue should be heated in a glass tube: if it sublime without change or decomposition, the metal was in the state of oxide; if the sublimed sulphuret be mingled with globules of metallic mercury, it was in the state of sub- oxide. B. 2, a. Special testing for Copper.—To a portion of the solution, ammonia in excess is added, a blue liquid is ob- tained. To another portion ferrocyanide of potassium is added, a chocolate brown precipitate is produced; presence of copper.
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