I. Potassium. Potassa

K = 39.03.

1. Potassa. - Koh = 55.99. Synonyms. - Potassium Hydrate. Potassium Hydroxide. Caustic Potash.

Source

Evaporate Liquor Potassae, fuse the residue and pour into clean cylindrical moulds which have been previously warmed.

Characters

Dry, white, translucent pencils, or fused masses, hard and brittle, showing a crystalline fracture; odorless, or having a faint odor of lye, and of a very acrid and caustic taste. Great caution is necessary in tasting and handling it, as it rapidly destroys organic tissues. Exposed to the air, it rapidly absorbs Carbon Dioxide and moisture, and deliquesces. Solubilit -In about 0.5 part of water and in 2 parts of alcohol.

Impurities

Organic matter, arsenic, lead, iron, soda, aluminum, calcium, chlorides, sulphates, silicates, carbonates, and nitrates.

Preparations

1. Liquor Potassae. Solution of Potassa. Synonym. - Solution of Potassium Hydrate. An aqueous solution of Potassium Hydrate (Koh =55.99), containing about 5 per cent. of the hydrate.

Source

Dissolve Potassium Bicarbonate in distilled water; slake Lime, dissolve in distilled water and boil, add this to the first solution, continue to l>oil, strain when cold; when it has become clear from subsidence, decant or siphon off the clear solution. K2Co3 + Ca(OH)2 = 2Koh + CaCo3. Or it may be prepared from a solution of Potassa, 56 parts of the full strength, directed by the U. S. P. (90 per cent.), in distilled water (944 parts).

Characters

A clear colorless liquid, odorless, having a very acrid and caustic taste, and a strong alkaline reaction. Sp. gr. about 1.036.

Impurities

See Potassa.

Incompatibles

Acids, acid salts, metallic salts and preparations of ammonia, belladonna, hyoscyamus and stramonium, the alkaloids of these three being decomposed by caustic potash. All alkaloids are precipitated by alkalies.

Dose, 5 to 30 m.; .30 to 2.00 c.c, freely diluted.