Sodium hydroxide has strong alkalinity and strong corrosiveness. It can be used as acid neutralizer, matching masking agent, precipitant, precipitation masking agent, color developing agent, saponification agent, peeling agent, detergent, etc. Sodium hydroxide has strong alkalinity and strong hygroscopicity. It is easy to dissolve in water and gives off heat when dissolving. The aqueous solution is alkaline and greasy. It is highly corrosive and corrosive to fibers, skin, glass and ceramics. It reacts with aluminum and zinc, non-metallic boron and silicon to give out hydrogen, disproportionation with halogen such as chlorine, bromine and iodine, neutralizing with acids to form salt and water.