Commonly known as caustic soda, caustic soda, caustic soda, is a strong caustic base, generally in the form of a sheet or particle, soluble in water(heat released when soluble in water) and forming an alkaline solution, Another deliquescent, It is easy to absorb water vapor(deliquescence) and carbon dioxide(deterioration) in the air. NaOH is one of the necessary chemicals in the chemical laboratory and is also one of the common chemicals. Pure products are colorless and transparent crystals. Density 2.130 g/cm3. Melting point 318.4 °C. Boiling point 1390 °C. Industrial products contain a small amount of sodium chloride and sodium carbonate, which is a white opaque crystal. There are lumps, flakes, granules, and sticks. Formula 40.01. Sodium hydroxide(NaOH) has a wide range of uses. For papermaking, soap, dyes, rayon, aluminum, oil refining, cotton fabric finishing, coal tar product purification, as well as food processing, wood processing and machinery industry.