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.

    24/272 (page 6)
    15. Mix two or three grains of dry, powdered chloride of ammonium very intimately with a like quantity of slaked lime ; place the mixture ina crucible, and warm it by means of a spirit or gas lamp; ammonia will be set free as in the previous experiment. 16. Dissolve a few grains of carbonate of soda in water ; add to the solution sulphuric, hydrochloric, or nitric acid— each of these acids deprives the carbonic acid of its base : it is consequently set free; and, by its escaping through the water into the atmosphere, causes an effervescence. 17. Place a few grains of chalk or marble at the bottom of a test-tube; cover it with water, and then add to it hydrochloric or nitric acid—either of these acids deprives carbonic acid of its base, consequently it is set free; and by its evolution, produces effervescence, as in the previous experiment. Hydrochloric and nitric acids are to be pre- ferred to sulphuric acid m this experiment, because the former give with lime, salts soluble in water; but the latter produces with that base, a salt, sulphate of lime, sparingly soluble in water; the greater part of the sulphate of lime therefore falls down, and thus shields the undecomposed chalk or marble from the acid. 18. The student will see by these two courses of experi- ments, that salts are decomposed by adding to them either acids or bases, provided the acids or bases added have stronger affinities than the acids or bases in the existing compound; and that, according as acids or bases are added, so acids or bases are set free. Thus, ammonia and alumina are liberated from their salts on the addition of a stronger base, and carbonic acid is liberated from its combinations on the addition of a stronger acid. 19. All the salts of ammonia containing volatile acids, on being heated volatilize completely, either with or without