Atoms. Equiv. wt. Per cent. Ammonia (NH_{3}) 1 17· 31·78 Hydrochloric acid (HCl) 1 36·5 68·22 --- ----- ------ Hydrochlorate of Ammonia (NH_{3}HCl) 1 53·5 100· Or, according to the ‘ammonium-theory,’ of—— Atoms. Equiv. wt. Per cent. Ammonium (NH_{4}) 1 18· 33·65 Chloride (Cl) 1 35·5 66·35 --- ----- ------ Chloride of Ammonium (NH_{4}Cl) 1 53·5 100· _Prop. &c._ The sal ammoniac of commerce is found under the form of large white hemispherical, cup-like cakes or masses (or in large fragments which are sections of them), possessing a tough, fibrous, semi-crystalline texture, and very difficult to powder. It is odourless, has a saline taste somewhat sharp or acrid, and sublimes without either fusion or decomposition. It slightly reddens litmus; dissolves in rather less than 3 parts of cold water, and in about 1 part of boiling water; is soluble in alcohol; and when crystallised from water, under favorable circumstances, forms distinct octahedra, or cubes, usually small and aggregated together in rays or feathery masses. By slowly evaporating its aqueous solution, it may be sometimes obtained in cakes an inch in thickness. It is anhydrous. Sp. gr. 1·450. _Pur._ It should give a colourless solution with water; wholly sublime with heat; and neither chloride of barium, nor sulphuretted hydrogen, should affect its solution. A solution, to which a few drops of nitric acid have been added, should not yield a blue precipitate with ferrocyanide of potassium. It often contains sesquichloride of iron, and sometimes lead; both of which may be readily detected by the above tests. Its complete volatility may be easily determined by heating, in the flame of a candle, a small fragment held on the point of a knife. _Tests._——1. It is known to be a salt of ammonium by its cooling ammoniacal fumes when triturated with lime, or when moistened with caustic potassa or soda:——2. It is shown to be a chloride by its solution yielding, with nitrate of silver, a white curdy precipitate, insoluble in boiling nitric acid, soluble in ammonia.