Sodium sulfite is an inorganic compound. It is a white granular powder at room temperature, soluble in water and reducing. It is disproportioned into sodium sulfide and sodium sulfate when heated and gradually oxidized into sodium sulfate when placed in air. It can exist in three forms: anhydrous matter, heptahydrate and decahydrate, of which anhydrous matter is the most difficult to be oxidized. Its aqueous solution is alkaline due to hydrolysis and releases toxic sulfur dioxide gas during acidification. Sodium sulfite can be prepared by introducing sulfur dioxide into sodium hydroxide solution. When sulfur dioxide is excessive, sodium bisulfite will be generated. Sodium sulfite can be used as developer, preservative of dried fruit and meat, Deoxidizer in printing and dyeing industry, and reducing chemical reagent. It is used in chemical industry and laboratory production and synthesis.
Manufacturing
