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Potassium bisulfite

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Potassium hydrogen sulfite or potassium bisulfite is a chemical compound with the chemical formula KHSO3. It is used during the production of alcoholic beverages as a sterilising agent. This additive is classified as E number E228 under the current EU approved food additive.[1]

Potassium bisulfite
Potassium bisulfite.svg
IUPAC name
Potassium hydrogen sulfite
Other names
Potassium bisulfite, potassium bisulphite solution, sulfurous acid, monopotassium salt, monopotassium sulfite
3D model (JSmol)
ECHA InfoCard 100.028.973
EC Number 231-870-1
E number E228 (preservatives)
Molar mass 120.1561 g/mol
Appearance White crystalline powder
Odor SO2
Melting point 190 °C (374 °F; 463 K) (decomposes)
49 g/100mL (20 °C)
115 g/100mL (100 °C)
Solubility Insoluble in alcohol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references


It is made by the reaction of sulfur dioxide and potassium carbonate. The sulfur dioxide is passed through a solution of the potassium carbonate until no more carbon dioxide is given off. The solution is concentrated and then allowed to crystallize.

See alsoEdit