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.

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    portion of the solution to which no arseniate of ammonia has been added, and continue the ignition until all the am- moniacal salts which have been added in the course of the analysis are expelled ; after their expulsion, as much boiling water as would fill a small-sized thimble should be poured into the vessel, in order to dissolve the fixed alkalies, if they are present. The liquor must then be filtered through a very small filter, and the clear filtered liquid examined for soda and potash by the blowpipe flame; when soda is pre- sent, Cartmell’s method (paragraph 112) must be adopted for the detection of potash. PARTICULAR OBSERVATIONS REGARDING THE PRECIPITATES PRODUCED BY THE GENERAL REAGENTS, AND THE PRECAUTIONS TO BE ATTENDED TO IN EXAMINING THE SOLUTIONS. 342. Precautions to be attended to in examining for the Jirst section of the Siath Group.—Before adding hydro- chloric acid to any solution under examination, it is neces- sary to ascertain, by test-papers, whether the solution is acid, neutral, or alkaline. When it is one of the two former, a few drops of the acid will generally be sufficient ; if alka- line, the acid must be added until it is decidedly in excess. When a precipitate is produced, add the acid, drop by drop, until it ceases to increase; then add a few drops more, shake the mixture, and filter. When no precipitate is pro- duced, a few drops of the acid will in most cases be sufficient, since our only object in adding it then is to acidify the solution, in order to prevent the precipitation of the mem-