Potassium hydroxide (chemical formula: KOH, formula: 56.1) white powder or flaky solid. Melting point 380 C, boiling point 1324 C, relative density 2.04g/cm3, refractive index n20/D1.421, vapor pressure 1 mmHg (719 C). Strong alkalinity and corrosiveness. It is easy to absorb water in the air and deliquescence, and absorb carbon dioxide to form potassium carbonate. Soluble in about 0.6 parts of hot water, 0.9 parts of cold water, 3 parts of ethanol, 2.5 parts of glycerol. When dissolved in water, alcohol or treated with acid, it produces a lot of heat. The pH of 0.1 mol/L solution is 13.5. Moderate toxicity, half lethal dose (rat, oral) 1230 mg/kg. Soluble in ethanol, slightly soluble in ether. It has strong alkalinity and corrosiveness, and its properties are similar to those of caustic soda. Moderate toxicity, half lethal dose (rat, oral) 1230 mg/kg.