By neutralizing hydrochloric acid with chalk or white marble, and adding to the solution a little chlorinated lime and slaked lime. In the first process carbonic acid is evolved and chloride of calcium formed:

2HC1 + CaCO3 = CaCl2 + CO2 + H1O.

In the second process the added lime frees the solution from iron and magnesia; it should then be filtered and evaporated to dryness at a temperature of 400° F. If the solution be simply evaporated, the chloride is left combined with water CaCl26(H1O), and it is only at a heat sufficient to fuse the mass that it parts with all its water.

Characters And Tests

This salt has a great absorbent power for water, is deliquescent, and very soluble; it occurs in crystals, or in whitish crystalline fragments of bitter, acrid, saline taste. It must be distinguished from calx chlorata (chloride of lime), and does not, like that compound, evolve chlorine on addition of hydrochloric acid.