Prep. By dissolving one ounce of hydrochlorate of ammonia in eight fluid ounces of distilled water, and afterwards making up the solution with distilled water to ten fluid ounces.

Use. It is used as a test under the heads of Magnesia, Carbonate and Sulphate of Magnesia, and Chloride of Iodium.

The solution of hydrochlorate of ammonia with a little free ammonia is mixed with the solution of the substance to be tested, and phosphate of soda is afterwards added, when the magnesia present is precipitated in the form of the ammonio-magnesian phosphate. No precipitate of this salt will take place (except in a very concentrated solution of magnesia) unless hydrochlorate of ammonia be present. A solution of chloride of sodium when treated in a similar manner should give no precipitate, showing the absence of magnesia. The precipitates caused in a solution of magnesian salts by potash, soda, and ammonia, and by the carbonate of potash and soda, are all soluble in hydrochlorate of ammonia.