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.

    40/272 (page 22)
    The mixture generally takes fire ; there is, however, no dan- ger, at least when no more than a quarter of a pound of ni- trate of potash has been used. Let the mass cool, and then treat it with cold water to dissolve out the soluble part ; filter this solution, and conduct carbonic acid into the filtrate. This serves to precipitate nearly the whole of the oxide of lead that has passed into the solution; a little sulphide of hydrogen will remove the remainder. Filter again, and evaporate the filtrate to dryness, stirring the mass towards the end of the operation; heat the dry residue to fusion, to destroy any hyposulphite of potash that may have been formed. Dissolve one part of the fused mass in two parts of water. 21. Ferrocyanide of potassium (yellow prussiate of potash).—Dissolve one part, by weight, in twelve, by mea- sure, of water. 22. Ferricyanide of potassiwm (red prussiate of potash). —Dissolve one part, by weight, of the salt, in twelve parts, by measure, of water. 23. Sulphocyanide of potassiwm.—Dissolve one part of the salt in ten parts of water. 24. Chromate of potash must be free from sulphuric acid. Dissolve one part, by weight, in eight parts, by measure, of water. 25. Caustic soda is prepared by dissolving one part, by weight, of carbonate of soda, in twelve parts, by measure, of water, and boiling the solution in a clean iron pan. Hy- drate of lime must be added in small portions to the boiling liquid, until hydrochloric acid causes no effervescence in a portion of the liquid. When this point has been attained, the pan must be removed from the fire, and the precipitate