Caustic soda is a white solid with strong hygroscopicity. It will melt and flow after absorbing moisture. It can absorb water and carbon dioxide in the air to produce sodium carbonate. It is brittle, soluble in water, alcohol, glycerin, but insoluble in acetone. A lot of heat is released when melting. The aqueous solution is slippery and alkaline. It is highly corrosive and can burn the skin and destroy the fibrous tissue. Contact with aluminum at high temperatures produces hydrogen. It can neutralize with acids and generate a variety of salts. Liquid sodium hydroxide (ie, soluble alkali) is a purple-blue liquid with a soapy and slippery feel, and its properties are similar to solid alkali.
The preparation of caustic soda is electrolytic or chemical. Chemical methods include lime causticization or ferrite.
The use of caustic soda is mainly used in synthetic detergents, soaps, papermaking; also used as a solvent for vat dyes and insoluble nitrogen dyes; also used in the production of petroleum, chemical fibers, and rayon; also used in medicine, such as the production of vitamin C Wait. It can also be used in organic synthesis and petroleum industries and directly used as a desiccant.