Characters. - A colourless syrupy liquid, without odour, and of a strongly acid taste and reaction, sp. gr. 1.347. When heated it loses water, and when a temperature of about 200° C. (392° F.) has been reached, the acid is gradually converted into pyro-phosphoric and metaphosphoric acids, which may be volatilised at a red heat.

Preparation. - Oxidising phosphorus by nitric acid. Vide p. 567.

reactions. - When diluted, and supersaturated with ammonia, the test-solution of magnesium gives a white precipitate. Vide also the reactions and tests of acidum phosphoricum dilutum.

Preparations containing Free Phosphoric Acid.

B.P

Acidum Phosphoricum Dilutum. Syrupus Ferri Phosphatis.

U.S.P

Acidum Phosphoricum Dilutum.