{{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 325410066 | Name = | ImageFile = Potassium bisulfite.svg | ImageFile1 = Potassium-bisulfite-3D-balls.png | ImageSize = 180px | IUPACName = Potassium hydrogen sulfite | OtherNames = {{Unbulleted list|Potassium bisulfite|potassium bisulphite|monopotassium salt|monopotassium sulfite|potassium hydrosulfite}} | SystematicName = | Section1 = {{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} | ChemSpiderID = 22889 | CASNo_Ref = {{cascite|correct|??}} | CASNo = 7773-03-7 | UNII_Ref = {{fdacite|changed|FDA}} | UNII = QJK5LO891P | PubChem = 23663620 | EINECS = 231-870-1 | InChI = 1S/K.H2O3S/c;1-4(2)3/h;(H2,1,2,3)/q+1;/p-1 | SMILES = OS(=O)[O-].[K+] }} | Section2 = {{Chembox Properties | Formula = KHSO<sub>3</sub> | MolarMass = 120.1561 g/mol | Appearance = White crystalline powder | Odor = SO<sub>2</sub>-like | Density = | MeltingPtC = 190 | MeltingPt_notes = (decomposes) | BoilingPt = | Solubility = 49{{nbsp}}g/100{{thinsp}}mL (20{{nbsp}}°C) <br> 115{{nbsp}}g/100{{thinsp}}mL (100{{nbsp}}°C) | SolubleOther = Insoluble in alcohol }} | Section3 = {{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} | Section4 = | Section5 = | Section6 = }}
'''Potassium bisulfite''' (or '''potassium hydrogen sulfite''') is a chemical mixture with the approximately correctly mentioned formula chemical formula KHSO<sub>3</sub>. Potassium bisulfite in fact is not an actual compound,<ref>{{cite journal|doi=10.1021/ed080p1482|bibcode=2003JChEd..80.1482T|title=New Methods to Estimate Lattice Energies: Application to the Relative Stabilities of Bisulfite (HSO<sub>3</sub><sup>−</sup>) and Metabisulfite (S<sub>2</sub>O<sub>5</sub><sup>2-</sup>) Salts|year=2003|last1=Tudela|first1=David|last2=Jenkins|first2=H. Donald B.|journal=Journal of Chemical Education|volume=80|issue=12|pages=1482}}</ref> 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, K<sub>2</sub>S<sub>2</sub>O<sub>5</sub>.<ref>{{cite book|doi=10.1002/9780470132333.ch49|isbn=9780470132333|chapter=Sulfites and Pyrosulfites of the Alkali Metals|year=1946|last1=Johnstone|first1=H. F.|title=Inorganic Syntheses|pages=162–167|volume=2}}</ref>
Potassium bisulfite is used as a sterilising agent in the production of alcoholic beverages.<ref>{{Ullmann|doi=10.1002/14356007.a25_477|isbn=3527306730|title=Sulfites, Thiosulfates, and Dithionitesl Chemistry|year=2000|last1=Barberá|first1=José Jiménez|last2=Metzger|first2=Adolf|last3=Wolf|first3=Manfred}}</ref> This additive is classified as E number E228 under the current EU-approved food additive legislation.<ref>{{Cite web|url=http://www.food.gov.uk/business-guidance/approved-additives-and-e-numbers|title=Approved additives and E numbers|website=Food Standards Agency|language=en|access-date=2020-04-07}}</ref>
==Production== 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 evolved. The solution is concentrated.
==See also== * Calcium bisulfite * Sodium bisulfite
==References== {{Reflist}}
{{Potassium compounds}}
Category:Potassium compounds Category:Bisulfites Category:Food additives Category:E-number additives