Synonym. Acidum Muriaticum Purum. Edin. Dub.

Prep. By the action of sulphuric acid and water on chloride of sodium (common salt) in a glass retort, sulphate of soda and hydrochloric acid are formed; the latter distils over, and is collected in a receiver containing water, which absorbs the gas rapidly.

Prop. & Gomp. A colourless transparent liquid, with a suffocating odour, and very sour taste, giving off white acrid fumes when exposed to air; sp. gr. 1.17; entirely dissipated by heat; it consists of hydrochloric acid (H Cl) dissolved in water. It gives with nitrate of silver a curdy white precipitate (chloride of silver), soluble in excess of ammonia, but not in nitric acid.

Hydrochloric acid has no action on gold leaf, even when boiled with it; this is shown by the acid, after digestion on the metal, not giving any precipitate with protochloride of tin; nor does the acid decolorize a solution of sulphate of indigo, indicating the absence of free chlorine. When diluted with 4 volumes of distilled water it gives no precipitate with chloride of barium or sulphuretted hydrogen, and does not tarnish bright copper foil when boiled with it, proving the absence of sulphates, and earthy or metallic matter; 1 fluid drachm requires for neutralization 60.25 measures of the volumetric solution of soda, corresponding to about 22 grains of real acid (H CI).

Off. Prep. Acidum Hydrochloricum Dilutum. Dilute Hydrochloric Acid. (Hydrochloric acid, three fluid ounces; distilled water, eight fluid ounces.)

[Acidum Muriaticum Dilutum. Muriatic acid, four troy ounces; distilled water to make the diluted acid measure a pint. The sp. gr. is 1.038. U. S.]

Its sp. gr. is 1.05; six fluid drachms require for neutralization ninety-nine measures of the volumetric solution of soda, equivalent to about thirty-six grains of real acid.