Bromous acid with the formula HBrO₂ has bromine in the +3 oxidation state

Oxidation state

In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...

. The salts of bromous acid are called bromites. The acid is not stable and only occurs as an intermediate, for example in the oxidation of hypobromite

Hypobromite

The hypobromite ion, also called alkaline bromine water, is BrO−. Bromine is in the +1 oxidation state. Hypobromite is the bromine compound analogous to hypochlorites found in common bleaches, and in immune cells...

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Chemistry

Bromous acid can be produced by classical chemical or electrochemicals method via anodic oxidation.

HBrO + HClO → HBrO₂ + HCl

Also disproportioning of hypobromous acid will give bromous acid and hydrobromic acid

Hydrobromic acid

Hydrobromic acid is a strong acid formed by dissolving the diatomic molecule hydrogen bromide in water. "Constant boiling" hydrobromic acid is an aqueous solution that distills at 124.3 °C and contains 47.6% HBr by weight, which is 8.89 mol/L. Hydrobromic acid has a pKa of −9, making it a...

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2 HBrO → HBrO₂ + HBr

Lastly, a synproportion reaction of bromic acid and hydrobromic acid gives bromous acid.

2 HBrO₃ + HBr → 3 HBrO₂

Compounds

Several bromites are stable and have been isolated. For example NaBrO₂· 3H₂O and Ba(BrO₂)₂·H₂O.

Use

Bromites can be used for the reduction of permanganate

Permanganate

A permanganate is the general name for a chemical compound containing the manganate ion, . Because manganese is in the +7 oxidation state, the permanganate ion is a strong oxidizing agent. The ion has tetrahedral geometry...

s to manganate

Manganate

In inorganic nomenclature, a manganate is any negatively charged molecular entity with manganese as the central atom. However, the name is usually used to refer to the tetraoxidomanganate anion, MnO, also known as manganate because it contains manganese in the +6 oxidation state...

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2MnO + BrO + OH⁻ → 2MnO + BrO + H₂O