Hypobromous acid is a weak, unstable

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...

with chemical formula of HOBr. It is mainly produced and handled in an aqueous solution. It is generated both biologically and commercially as a

disinfectant A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than st ...

. Salts of

hypobromite The hypobromite ion, also called alkaline bromine water, is BrO−. Bromine is in the +1 oxidation state. The Br–O bond length is 1.82 Å. Hypobromite is the bromine compound analogous to hypochlorites found in common bleaches, and in immune cel ...

are rarely isolated as solids.

Synthesis and properties

Addition of bromine to water gives hypobromous acid and

hydrobromic acid Hydrobromic acid is a strong acid formed by dissolving the diatomic molecule hydrogen bromide (HBr) in water. "Constant boiling" hydrobromic acid is an aqueous solution that distills at and contains 47.6% HBr by mass, which is 8.77 mol/L. H ...

(HBr) via a disproportionation reaction. : Br₂ + H₂O HOBr + HBr In nature, hydrobromous acid is produced by

bromoperoxidase Bromide peroxidase (, ''bromoperoxidase'', ''haloperoxidase (ambiguous)'', ''eosinophil peroxidase'') is a family of enzymes with systematic name ''bromide:hydrogen-peroxide oxidoreductase''. These enzymes catalyses the following chemical reacti ...

s, which are enzymes that catalyze the oxidation of bromide with hydrogen peroxide: : Br⁻ + H₂O₂ HOBr + OH⁻ Hypobromous acid has a p''K''_a of 8.65 and is therefore only partially dissociated in water at pH 7. Like the acid, hypobromite salts are unstable and undergo a slow disproportionation reaction to yield the respective bromate and bromide salts. : 3 BrO⁻(aq) → 2 Br⁻(aq) + (aq) Its chemical and physical properties are similar to those of other hypohalites.

Uses

HOBr is used as a

bleach Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to ...

, an oxidizer, a

deodorant A deodorant is a substance applied to the body to prevent or mask body odor due to bacterial breakdown of perspiration or vaginal secretions, for example in the armpits, groin, or feet. A subclass of deodorants, called antiperspirants, prevents ...

, and a

, due to its ability to kill the cells of many pathogens. The compound is generated in warm-blooded vertebrate organisms especially by

eosinophils Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells (WBCs) and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. ...

, which produce it by the action of eosinophil peroxidase, an enzyme which preferentially uses bromide. Bromide is also used in hot tubs and spas as a germicidal agent, using the action of an oxidizing agent to generate hypobromite in a similar fashion to the peroxidase in eosinophils. It is especially effective when used in combination with its congener, hypochlorous acid.

References

{{bromine compounds Hypobromites Hydrogen compounds Oxidizing acids Oxidizing agents Halogen oxoacids