Potassium sulfite

Potassium sulfite
Names
	IUPAC name Potassium sulfite
	Other names E225
Identifiers
CAS Number	10117-38-1 ;
3D model (JSmol)	Interactive image;
ChemSpider	23332 ;
ECHA InfoCard	100.030.279
E number	E225 (preservatives)
PubChem CID	24958;
UNII	015KZC652E ;
CompTox Dashboard (EPA)	DTXSID80889532 ;
	InChI InChI=1S/2K.H2O3S/c;;1-4(2)3/h;;(H2,1,2,3)/q2+1;/p-2 Key: BHZRJJOHZFYXTO-UHFFFAOYSA-L ; 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 cm3/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).
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	Infobox references

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.

Use

Potassium sulfite is widely used for preserving food and beverages.

Production and reactions

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

K₂S₂O₅ → K₂SO₃ + SO₂

References

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

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