Sulfurous acid

Sulfurous acid is a weak acid with the chemical formula H₂SO₃. 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 chemical structure

Sulfurous acid has two tautomers, or chemical structures that easily change into each other. One is the SO(OH)₂ form, and the other is a sulfonic acid, HSO₂OH. The bisulfite ion, when sulfurous acid loses only one hydrogen atom, has the shape of the sulfonic acid tautomer.^[1]

Related pages

• Sulfuric acid
• Sulfate
• Sulfur