Sodium Sulfite

Sodium sulfite acts as a reducing, bleaching, and sulfiting agent, and serves as a preservative.
If treated with strong acids, sulfur dioxide is released.
Elemental sulfur dissolves in aqueous solutions of sodium sulfide through the formation of sodium thiosulfate.

In the food industry: As a preservative with the code E 221,
In the photo/printing industry: In preventing oxidation,
In the textile industry: In removing active chloride,
In the leather industry: In sulfiting tanning extracts,
In the explosives industry: In the production of Trinitrotoluene (TNT),
In the rubber industry: In stabilizing latex,
In the chemical industry: In the production of Sodium Thiosulfate, as a reducing agent in sulfonation and sulfomethylation,
In the fiber industry: In coagulant baths for dissolving raw materials, as a bleaching agent for removing sulfur from yarn,
In water treatment: In preventing corrosion in steam boilers, in the electroplating industry, in treating boiled water,
In the paper and pulp industry: In the kraft process, widely used for chemical lignin removal from wood and fiber separation, where the main active components are Sodium Hydroxide and Sodium Sulfite