Potassium sulfite

Potassium sulfite is the inorganic compound with the formula K₂SO₃. It is the salt of potassium cation and sulfite anion. It is a white solid that is highly soluble in water.

Potassium sulfite

Names
IUPAC name Potassium sulfite
Other names E225
Identifiers
CAS Number	10117-38-1^Y
3D model (JSmol)	Interactive image
ChemSpider	23332^N
ECHA InfoCard	100.030.279
E number	E225 (preservatives)
PubChem CID	24958
UNII	015KZC652E^N
CompTox Dashboard (EPA)	DTXSID80889532
InChI InChI=1S/2K.H2O3S/c;;1-4(2)3/h;;(H2,1,2,3)/q2*+1;/p-2^N Key: BHZRJJOHZFYXTO-UHFFFAOYSA-L^N InChI=1/2K.H2O3S/c;;1-4(2)3/h;;(H2,1,2,3)/q2*+1;/p-2 Key: BHZRJJOHZFYXTO-NUQVWONBAU
SMILES [O-]S(=O)[O-].[K+].[K+]
Properties
Chemical formula	K2SO3
Molar mass	158.26 g/mol
Appearance	White solid
Solubility in water	Soluble
Acidity (pKa)	8
Magnetic susceptibility (χ)	−64.0·10^−6 cm^3/mol
Hazards
Flash point	Non-flammable
Related compounds
Other anions	Potassium sulfate Potassium selenite
Other cations	Sodium sulfite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is ^YN ?)
Infobox references

Use

Potassium sulfite is widely used for preserving food and beverages.

Production and reactions

Main article: Sulfite § Reactions

Potassium sulfite is produced by the thermal decomposition of potassium metabisulfite at 190°C:[1]

K₂S₂O₅ → K₂SO₃ + SO₂

References

1. Johnstone, H. F. (1946). "Sulfites and Pyrosulfites of the Alkali Metals". Inorganic Syntheses. 2: 162–167. doi:10.1002/9780470132333.ch49. ISBN 9780470132333.