Sodium hydroxide, also known as caustic soda, caustic soda, caustic soda, and flake caustic soda, is an inorganic compound with the chemical formula NaOH and a relative molecular weight of 39.9970.
Physical properties
Density: 2.130 g/cm³
Melting point: 318.4℃(591 K)
Boiling point: 1390℃ (1663 K)
Vapor pressure: 24.5mmHg(25°C)
Saturated vapor pressure: 0.13 Kpa (739℃)
Appearance: white crystalline powder
Solubility: easily soluble in water, ethanol, glycerol, insoluble in acetone, ether
Chemical properties
Sodium hydroxide is corrosive to fibers, skin, glass, ceramics, etc. It releases heat when dissolved or diluted as a concentrated solution; it can also generate a lot of heat when it reacts with inorganic acids to generate corresponding salts; it reacts with metal aluminum and zinc, non-metal boron and silicon to release hydrogen; it reacts with halogens such as chlorine, bromine, and iodine to undergo disproportionation reactions. It can precipitate metal ions from aqueous solutions to form hydroxides; it can cause oils and fats to undergo saponification reactions to generate corresponding organic acid sodium salts and alcohols, which is the principle of removing oil stains from fabrics.