Bisulfite
The bisulfite ion (IUPAC-recommended nomenclature: hydrogensulfite) is the ion HSO−
3.  Salts containing the HSO−
3 ion are also known as "sulfite lyes". Sodium bisulfite is used interchangeably with sodium metabisulfite (Na2S2O5). Sodium metabisulfite dissolves in water to give a solution of Na+HSO−
3.
- Na2S2O5 + H2O → 2 Na[HSO3]