Sodium sulfite
In chemistry, sodium sulfite is a soluble compound of sodium. Its chemical formula is Na2SO3. It is used for SO2 scrubbing, a part of the flue gas desulfurisation process. It is also used as a preservative to prevent dried fruit from discoloring, and for preserving meats, and is used in the same way as sodium thiosulfate to convert elemental halides to their respective acids, in photography and for reducing chlorine levels in pools.