Elements of chemistry, in two volumes / by John Murray.

  • Murray, John.
Date:
1828
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry, in two volumes / by John Murray. Source: Wellcome Collection.

    58/768 (page 46)
    Suli-BonATE of Potash, like several other borates, contains an excess of alkali; it is soluble in water; by evaporation, its solution affords prismatic crystals, which are not changed by exposure to the air. Muriate of Potash has a taste saline and slightly bit- ter : it is soluble in 3 parts of cold, and in half its weight of boiling water, the latter solution crystallizing on cool- ing ; the crystals have a cubic form, and decrepitate when heated, from the loss of water. As this water is dissipated, the nature of the substance changes; the oxygen of the potash, it is conceived, unites with the hydrogen of the acid ; and when the mass is completely dried, it is no longer a salt, contains neither acid nor alkali, but is a chloride of potassium. The same substance is formed when potassium is burnt in chlorine gas: it is composed of one atom of chlorine, 36, and one of potassium, 40. Chloride of Potash must evidently be formed where chlorine is condensed by a dilute solution of potash, since / the alkaline properties are neutralized. The liquid still retains the power of destroying vegetable colours. The compound, however, cannot be obtained insulated, as by concentration of the solution decomposition takes place, and a chlorate is formed. Chlorate of Potash.—To prepare this salt, a solu- tion of potash is put into the bottles of Woolfe’s appara- tus, and a current of chlorine gas is passed through it, from a retort containing sea salt, sulphuric acid, and oxide of manganese: this is continued until the alkali is neutralized ; the chlorate of potash is deposited in scales, while a portion of muriate of potash remains in solution ; one portion therefore of the chlorine combines with the hydrogen of the water forming muriatic acid, while the rest of the chlorine, uniting with the oxygen of the de- composed water, becpmes chloric acid. I he two acids