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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    the cover after each addition. When the whole has been added, the ignition must be continued for a short time, until the excess of sulphur has been dissipated. 9. Sulphurous acid is prepared by acting upon copper or charcoal with sulphuric acid. For this purpose small pieces of charcoal are introduced into a flask, with from six to eight times their weight of sulphuric acid, and a mo- derate heat applied. The evolved gas must be conducted into cold water until it is no longer absorbed. On account of the great tendency which this reagent has to absorb more oxygen, and become converted into sulphuric acid, it must be preserved in well-stoppered bottles. 10. Chlorine gas is prepared by introducing into a flask one part of peroxide of manganese along with four parts of hydrochloric acid; the liberation of the chlorine is assisted by a gentle heat. A solution of the gas may be prepared by passing it into cold water. Chlorine water must be kept in well-stoppered bottles, and excluded from the light. 11. Oxalic acid.—Dissolve one part, by weight, of the acid, in twenty parts, by measure, of water. 12. Oxalate of ammonia must be free from sulphuric acid. Dissolve one part, by weight, of the salt, in twenty parts, by measure, of water. 13. Ammonia ought to be free from non-volatile matter, and also from carbonic, sulphuric, and hydrochloric acid. Dilute one part of the strong ammonia with four of water. 14. Chloride of ammonium is frequeutly contaminated with iron, from which it ought to be entirely free. Dissolve one part, by weight, of the salt, in ten parts, by measure, of water. 15. Sulphide of ammonium (hydrosulphuret of ammonia) is prepared by passing hydrosulphuric acid through liquid