Sodium sulfite for medicine

Sodium sulfite used in medicine is easily weathered in the air and oxidized to sodium sulfate. Crystal water will be lost at 150°C. When reheated, it melts into a mixture of sodium sulfide and sodium sulfate. The density of the anhydrous substance is 2.633. It oxidizes much slower than hydrate and does not change in dry air. When heated, it will decompose into sodium sulfide and sodium sulfate, which will contact with strong acid and decompose into corresponding salt to release sulfur dioxide. Sodium sulfite has strong reducing properties. It can reduce copper ions to cuprous ions (sulfites can form complexes with cuprous ions and stabilize), and can also reduce weak oxidants, such as phosphotungstic acid. In the laboratory, sodium sulfite and its hydrogen salt can be used to remove ether peroxides (add a small amount of water, stir a little, separate the liquid, dry the ether layer with quicklime, for some less demanding reactions). Can be separated with hydrogen sulfide.

Sodium sulfite is soluble in water, and the aqueous solution is alkaline. Slightly soluble in alcohol. Insoluble in water and ammonia. As a strong reducing agent, it reacts with sulfur dioxide to form sodium bisulfite, and reacts with strong acid to form the corresponding salt and release sulfur dioxide. As a strong reducing agent, sodium sulfite is easy to oxidize in humid air and sunlight, but it is more stable than sodium sulfite heptahydrate and decomposes when heated.