Tablets from caustic soda factories are highly corrosive, absorbent and deliquescent, and can be used as desiccants. However, acid gases such as sulfur dioxide, carbon dioxide, nitrogen dioxide and hydrogen chloride cannot be dried because sodium hydroxide reacts with carbon dioxide. It reacts with acid gases. Liquefaction, deliquescence and liquefaction in air (due to apparent dissolution, water absorption, physical changes); sodium hydroxide dissolves in water and has a lot of heat. Phenolphthalein can cause red, blue and purple litmus solutions to be attributed to strong alkali. Aluminum does not corrode plastics. Sodium hydroxide dust affects eyes and respiratory tract, corneal nasal septum; splashes onto skin, especially mucosal mucosa, can attack soft skin, and can penetrate deep into the skin, leaving scars after burns; splashes into the eye, not only damage the cornea, so that the eyes may arrange deep injury, serious blindness; can cause digestive tract burns, pain, mucosal ulcers, vomiting and blood gastric contents, bloody diarrhea. Sometimes, dumbness, dysphagia, shock, perforation of digestive tract and delayed gastrointestinal stricture may occur. Sodium hydroxide is alkaline and can pollute water. Pay attention to plants and aquatic organisms. In industry, caustic soda is usually called caustic soda, or caustic soda, caustic soda. This is because the sodium hydroxide solution splashes more strongly on the skin, eroding the epidermis and causing burns. It has the function of dissolving protein and is highly corrosive and corrosive (because it has the ability to dissolve protein, alkali burn is more difficult to cure than acid burn). Dropping rabbit eyes with 0.02% solution can cause corneal epithelial damage. LD50:40 mg/kg in abdominal cavity of mice and LDLo:500 mg/kg in rabbits.