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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    8. If to a solution of any of the soluble salts of the insoluble bases a soluble base is added, the soluble base will take away the acid from the insoluble base; the latter—viz., the insoluble base—being set free, will con- sequently precipitate, on account of its insolubility in the liquid. We may here observe, that many of the bases, when they are set free in this manner, combine with water ; this compound of the base and water is termed the hydrate of the base, whichever base it may be. ‘The three following experiments are given to teach the student the principle just stated; he must, therefore, carefully perform the expe- riments according to the directions: EXERCISES. 9. Dissolve, by the aid of heat, two or three grains of alum, which is a compound containing sulphate of alumina, in a test-tube half filled with water ; add ammonia to the solution after the alum is dissolved, and, after the addition, close the mouth of the test-tube with the thumb, and then shake the liquidin it very violently. Ifthe liquid smells of ammonia after the agitation, a sufficient quantity has been added; but if it does not, a further quantity of ammonia must be added, and the liquid again shaken ; and this must be repeated until the liquid smells of ammonia, after it has been well shaken. The ammonia deprives the alumina of its acid; the alumina, on being set free, combines with water —this compound of alumina and water appears under the form of a white, gelatinous solid, insoluble in water. 10. Dissolve two or three grains of sulphate of cop- per in a test-tube half filled with water; boil the so- lution, by means of a spirit or gas lamp, and add to the boiling liquid a solution of caustic soda, until it