Chemistry Formulas

Hypobromous Acid

The Hypobromous Acid Formula is a formula of a weak and unstable acid that has a similar chemical and similar physical property as of the hypohalites. Moreover, the hypohalites are the oxyanion that has the halogen in the oxidation state +1. However, the hypobromous acid has the ability to kill the pathogens and bacterias hence we use it as a disinfectant, oxidizer, bleach, and deodorant at the same time.


The hypobromite ion has a chemical formula i.e. (BrO−). Moreover, the bromine here is in the +1 oxidation state. The hypobromite is the bromine compound analogous to the hypochlorites present in some of the common bleaches, and in the immune cells as well. In various ways, the hypobromite functions in the same way as the hypochlorite and is also useful as a germicide and ant parasitic.

Formula and Structure

The molecular formula or we can say the chemical formula that we are having for the chemical compound hypobromous acid is HBrO. Moreover, an image showing its chemical structure is given below in the form of a picture in some common representations that we generally use for the organic molecules.

Hypobromous Acid Formula

When bromine reacts with the water, the hypobromous acid is the result that we obtain from this reaction:

Br2 + H2O ⇄ HOBr + HBr

Chemical Properties

The chemical compound hypobromous acid has a molecular weight of about 96.911 g/mol. In addition, the density of this chemical compound hypobromous acid i.e. (HBrO) is 2.470 g/cm. It has an acidity level of (pKa) 8.65. Whereas, it has a boiling point of 20 to 25 °C.

Synthesis and Properties

The process of the addition of bromine with the water results in the hypobromous acid and the hydrobromic acid (HBr) through a disproportionation reaction:

Br2 + H2O ⇄ HOBr + HBr

In nature, the hypobromous acid forms by the bromoperoxidases, which are the enzymes that catalyze the oxidation of the bromide with the hydrogen peroxide:

Br- + H2O2 ⇄ HOBr + OH-

The hypobromous acid has a pKa level of about 8.65 and is therefore only incompletely dissociated inside the water at a pH level of 7. However, just like the acid, the hypobromite salts are unstable and undergo a very slow and inconsistent disproportionation reaction process to yield the respective bromate and the bromide salts.

3BrO − (aq) → 2Br − (aq) + BrO − 3(aq)

Its chemical and physical properties are the same as those of the other hypohalites.


The HOBr is useful as a bleach, as an oxidizer, as a deodorant, and also as a disinfectant, due to its ability to destroy and finish the cells of many pathogens. Moreover, the compound is generated in the vertebrate organisms that have warm blood, especially by eosinophils.

The eosinophils produce it by the action of the eosinophil peroxidase that is an enzyme that preferentially uses the bromide. The bromide is also useful in hot tubs and spas as we can use it as a germicidal agent, using the action of an oxidizing agent to generate the hypobromite in the same fashion to the peroxidase in the eosinophils. It is especially very much effective when we use it in a combination with its congener that is the hypochlorous acid.

Solved Example for You


Arrange these in the decreasing orders of their acidic strength:



(A). HBrO > HClO > HIO.

(B). HClO > HBrO > HIO.

(C). HIO > HBrO > HClO.

(D). HClO > HIO > HBrO.

Answer: (B). HClO > HBrO > HIO.

The answer (HClO > HBrO > HIO) is on the basis of the electronegativity of the halogen.

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