Sulfurous acid

Sulfurous acid is a weak acid with the chemical formula . It is produced by dissolving sulfur dioxide in water. Bases deprotonate (remove the hydrogen ion) it to produce sulfites. It tends to turn back into sulfur dioxide and water again. It is a weak reducing agent.

Sulfurous acid has two tautomers, or chemical structures that easily change into each other. One is the  form, and the other is a sulfonic acid, . The bisulfite ion, when sulfurous acid loses only one hydrogen atom, has the shape of the sulfonic acid tautomer.

Related pages
Sulfuric acid
Sulfate
Sulfur

References

Category:Oxoacids
Category:Sulfur compounds