caustic soda, chemical formula for the NaOH, commonly known as caustic soda, caustic soda, caustic soda, as a strong corrosive strong alkali, usually flaky or massive form, soluble in water (dissolved in water when the heat) and The formation of alkaline solution, and another deliquescence, easy to absorb the water vapor (deliquescence) and carbon dioxide (deterioration), can be added to the hydrochloric acid test whether the deterioration. NaOH is one of the chemical chemicals in the chemical laboratory and one of the most common chemicals. Pure is a colorless transparent crystal. Density of 2.130g / cm³. Melting point 318.4 ° C. The boiling point of 1390 ° C. Industrial products contain a small amount of sodium chloride and sodium carbonate, is a white opaque crystal. There are blocks, flakes, granules and rods. The amount of 39.997. Sodium hydroxide in water treatment can be used as alkaline cleaning agent, soluble in ethanol and glycerol; insoluble in propanol, ether. And chlorine, bromine, iodine and other halogen disproportionation reaction. And acid from the role of the formation of salt and water.