CAS:1310-73-2
Molecular formula: NaOH
Molecular weight: 39.99
Physicochemical properties: pure anhydrous sodium hydroxide is white, translucent and crystalline solid. It has strong corrosivity and water absorption and can be used as desiccant. However, it can not dry sulfur dioxide, carbon dioxide and hydrogen chloride gases. It is easy to deliquesce in the air, and sodium hydroxide is very soluble in water. The solubility increases with the increase of temperature. A lot of heat can be released during dissolution. At 288k, the concentration of saturated solution can reach 16.4mol/l (1:1). Its aqueous solution is astringent and greasy. The solution is strongly alkaline and has all the general properties of alkali. There are two kinds of commercial caustic soda: solid and liquid: pure solid caustic soda is white, block, flake, rod, granular and brittle; Pure liquid caustic soda is a colorless and transparent liquid. Sodium hydroxide is also soluble in ethanol and glycerol; But insoluble in ether, acetone and liquid ammonia. It has corrosive effect on fiber, skin, glass and ceramics, and will release heat when dissolved or diluted with concentrated solution; Neutralization reaction with inorganic acid can also produce a lot of heat and generate corresponding salts; React with metal aluminum and zinc, non-metallic boron and silicon to release hydrogen; Disproportionation reaction with halogen such as chlorine, bromine and iodine. It can precipitate metal ions from aqueous solution into hydroxide; It can saponify the oil and produce the sodium salt and alcohol of the corresponding organic acid, which is the principle of removing the oil on the fabric.
Product application: sodium hydroxide is widely used. In chemical experiments, in addition to being used as reagent, it can also be used as alkaline desiccant because of its strong hygroscopicity. Caustic soda is widely used in the national economy, and many industrial departments need caustic soda. The sectors that use caustic soda most are the manufacturing of chemicals, followed by papermaking, aluminum smelting, tungsten smelting, rayon, artificial cotton and soap manufacturing. In addition, in the production of dyes, plastics, pharmaceuticals and organic intermediates, the regeneration of old rubber, the electrolysis of metal sodium and water, and the production of inorganic salts, a large amount of caustic soda should also be used to prepare borax, chromium salt, manganate, phosphate, etc.