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.

    51/272 (page 33)
    water, and examined for potash by tartaric acid or bi- chloride of platinum. HOW THE WORK IS TO BE STUDIED. 76. The mode of separating one substance from another, and the properties and appearances of the precipitates, are the first things to be studied in qualitative analysis. The student gains this preparatory knowledge by performing the different experiments pointed out in the special tables, carefully noting the reactions which the reagents give with each individual member, and explaining by diagrams the decompositions produced. 77. These remarks may be illustrated by an example. The first group, and therefore the one which first claims the attention of the student, is made up of three members, viz., Portas, Sopa, and Ammonia. In the jirst para- graph, ander the head AMmonta, it is stated that this sub- stance and its salts are volatile, t.e. they can be converted by heat into vapour. In the second paragraph it is stated that all salts of ammonia are decomposed on the addition of a stronger base, gaseous ammonia being given off. In the third, that tartaric acid produces, in neutral and alkaline solutions of ammonia, a white, crystalline precipitate of bitartrate of ammonia. He has, therefore, to perform and verify these experiments, to notice those conditions which favour the reactions and those which prevent their develop- ment. 78. Let bitartrate of ammonia be taken as an example of what has just been said. It is stated in the table that this precipitate is produced both in neutral and alkaline solu- tions, but that free alkalies and free mineral acids dissolve it. Hence it follows, that though tartaric acid produces a 2§