Quantitative chemical analysis by electrolysis / by Alexander Classen in co-operation with Walter Löb ; authorized translation ... by William Hale Herrick and Bertram B. Boltwood.

  • Classen, Alexander, 1843-1934.
Date:
1898
Catalogue details

Licence: Public Domain Mark

Credit: Quantitative chemical analysis by electrolysis / by Alexander Classen in co-operation with Walter Löb ; authorized translation ... by William Hale Herrick and Bertram B. Boltwood. Source: Wellcome Collection.

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    as double oxalates. The beaker is covered, and left standing in a warm place for six hours; the precipitate is then ültered elf, washed with a mixture of ecpial volumes of acetic acid, water, and alcohol, and dissolved, after drying, in ammonium oxalate. Zinc, cobalt, and nickel are separated from man- ganese and magnesium as directed p. 251. The filtrate from the oxalates is completely freed from alcohol and acetic acid by evaporation, and iron, aluminium, and manganese 8e2)arated as directed pp. 194-108. As the (piantity of zinc, cobalt, etc., is generally very small, it is best, in order to facilitate the separation of the oxalates and the collection of the precipi- tate, to add about 0.2 g magnesium in the form of chloride,* so that magnesium oxalate is preci])itated with the other oxalates. In this case, the magnesium in pig iron, if present at all, is determined in another portion, together with some other metal (e.g., copper). If magnesium is used, all the manganese is found in the precipitate produced by acetic acid. To determine manganese alone in pig iron, either an aliquot part of the hydrochloric acid solution, or a separate portion of 0.2—0.5 g iron may be taken, and the determina- tion conducted as directed under Spathic Ii'on Ore, ]). 239. If copper is to be determined, the solution freed from acid and preferably oxidized is treated with ammonium oxalate in great excess, and electrolyzcd as already directed. The hydrochloric - acid solution may also be precipitated with hydrogen sulphide, and the cop2:)er determined in nitric acid solution (see p. 156). Determination of Arsenic and Antimony. Since these metals are j^resent only in very small quantity, about 10 g pig iron are used for their determination, and * Dissolve nuiguesiuni oxide in hydrochloric acid, and remove the free acid by evaporation.