Chloride of Gold. (See [Gold, Chloride of.])
Chloride of Sodium.
Symbol, NaCl. Atomic weight, 60.
Common salt exists abundantly in nature, both in the form of solid rock-salt and dissolved in the waters of the ocean.
Properties of the pure Salt.—Fusible without decomposition at low redness, but sublimes at higher temperatures; the melted salt concretes into a hard white mass on cooling. Nearly insoluble in absolute alcohol, but dissolves in minute quantity in rectified spirit. Soluble in three parts of water, both hot and cold. Crystallizes in cubes, which are anhydrous.
Impurities of Common Salt.—Table salt often contains large quantities of the chlorides of magnesium and calcium, which, being deliquescent, produce a dampness by absorption of atmospheric moisture: sulphate of soda is also commonly present. The salt may be purified by repeated recrystallization, but it is more simple to prepare the pure compound directly, by neutralizing hydrochloric acid with carbonate of soda.
Chloride of Silver. (See [Silver, Chloride of.])
This acid is found abundantly in lemon-juice and in lime-juice. It occurs in commerce in the form of large crystals, which are soluble in less than their own weight of water at 60°.
Commercial citric acid is sometimes mixed with tartaric acid. The adulteration may be discovered by making a concentrated solution of the acid and adding acetate of potash; crystals of bitartrate of potash will separate if tartaric acid be present.