In chemistry, sodium sulphite is a soluble compound of sodium. Its chemical formula is Na₂ SO₃. It has a molecular weight of 126.04. It is a product of SO₂ scrubbing, a part of the flue gas desulphurisation 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 thiosulphate to convert elemental halides to their respective acids, in photography and for reducing chlorine levels in pools.