Lime is commonly prepared from its carbonate (marble or limestone) by heating it to full redness to drive off the carbonic acid.

Characters And Tests

A grayish-white solid, of sp. gr. 3.18, of alkaline, caustic taste. When water is poured on it to the amount of about three-fourths of its weight, it swells up, evolving great heat (up to 500° F.), and falls into a soft, white powder, in which the oxide is combined with one molecule of water (hydrate of calcium, CaH1O2, = 74); the process is called "slaking."