Manual of qualitative analysis / by Robert Galloway.

  • Galloway, Robert.
Date:
1861
Catalogue details

Licence: Public Domain Mark

Credit: Manual of qualitative analysis / by Robert Galloway. Source: Wellcome Collection.

    39/272 (page 21)
    ammonia until it no longer produces a precipitate in a solu- tion of magnesia. Dilute one part with three of water. 16. Carbonate of ammonia must be free from non-volatile matter, and likewise from sulphuric acid. Dissolve one part, by weight, of the salt, in four parts, by measure, of water, and add one measure of ammonia. 17. Arseniate of ammonia is prepared by neutralizing arsenic acid with carbonate of ammonia, and evaporating to dryness. Dissolve one part, by weight, of the salt, in ten parts, by measure, of water. Arsenic acid is prepared by dissolving arsenious acid in nitric acid, mixed with a little hydrochloric acid, evapo- rating the solution to dryness, and igniting somewhat below a low red heat, until all nitric acid is expelled. 18. Molybdate of ammonia.—Digest molybdie acid in ammonia until complete solution is effected; filter the colourless fluid. Solution of molybdate of ammonia, mixed with nitric acid or hydrochloric acid until the precipitate which forms at first is redissolved, must remain colourless upon boiling. If it acqnires a yellow tint, the reagent con- tains phosphoric acid, and is unfit for use (supposing always, of course, that the hydrochloric or nitric acid was perfectly pure). 19. Sulphate of potash.—Dissolve one part, by weight, of the salt, in two hundred parts, by measure, of water. 20. Nitrite of potash is prepared by fusing one part of nitrate of potash in an iron pan, then adding two parts of lead, and keep stirring the mixture with an ironrod. The lead oxidizes in a great measure, even at a dull-red heat, changing to a yellow powder. To oxidize the last remaining particles of the metal, increase the heat to visible redness.