Potassium bisulfite

Potassium bisulfite
Names
IUPAC name
Potassium hydrogen sulfite
Other names
  • Potassium bisulfite
  • potassium bisulphite
  • monopotassium salt
  • monopotassium sulfite
  • potassium hydrosulfite
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.028.973
EC Number
  • 231-870-1
E number E228 (preservatives)
UNII
  • InChI=1S/K.H2O3S/c;1-4(2)3/h;(H2,1,2,3)/q+1;/p-1
  • OS(=O)[O-].[K+]
Properties
KHSO3
Molar mass 120.1561 g/mol
Appearance White crystalline powder
Odor SO2-like
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

Potassium bisulfite (or potassium hydrogen sulfite) is a chemical mixture with the approximately correctly mentioned formula chemical formula KHSO3. Potassium bisulfite in fact is not an actual compound, but a mixture of salts that dissolve in water to give solutions composed of potassium ions and bisulfite ions. It is a white solid with an odor of sulfur dioxide. Attempts to crystallize potassium bisulfite yield potassium metabisulfite, K2S2O5.

Potassium bisulfite is used as a sterilising agent in the production of alcoholic beverages. This additive is classified as E number E228 under the current EU-approved food additive legislation.