Present name. - Potassic Citrate. K3C6H5O7.
Made by neutralizing Citric Acid with Carbonate of Potash and evaporating to dryness.
Characters and Tests. - A white powder of saline, feebly acid taste, deliquescent, and very soluble in water. Heated with Sulphuric Acid, it forms a brown fluid, gives off an inflammable gas, and evolves the odour of Acetic Acid. Its solution, mixed with a solution of Chloride of Calcium, remains clear till it is boiled, when a white precipitate separates, readily soluble in Acetic Acid. Its solution, acidulated with Hydrochloric Acid, gives a yellow precipitate with Perchloride of Platinum. 102 grains heated to redness till gases cease to be evolved, leave an alkaline residue, which requires for exact neutralization 1,000 grain measures of the volumetric solution of Oxalic Acid.
Preparations. - Trituration. Solution in distilled water.
A fragmentary proving may be found in Brit. Journ. Horn., vol. xi.