hydrobromic acid

Hydrobromic acid
Identifiers
CAS number	10035-10-6 Y
EC number	233-113-0
RTECS number	MW3850000
Properties
Molecular formula	HBr
Molar mass	80.91 g/mol
Appearance	colorless liquid
Density	variable
Melting point	variable
Boiling point	variable
Solubility in water	aqueous solution
Acidity (pKa)	−9
Hazards
MSDS	ICSC 0282
EU Index	035-002-01-8
EU classification	Corrosive (C)
R-phrases	R34, R37
S-phrases	(S1/2), S7/9, S26, S45
NFPA 704	0 3 0
Flash point	Non-flammable
Related compounds
Other anions	Hydrofluoric acid Hydrochloric acid Hydroiodic acid
Related compounds	Hydrogen bromide
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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. Hydrobromic acid has a pK_a of −9, making it a stronger acid than hydrochloric acid, but not as strong as hydroiodic acid. Hydrobromic acid is one of the strongest mineral acids known.

Uses

Hydrobromic acid is mainly used for the production of inorganic bromides, especially the bromides of zinc, calcium, and sodium. It is a useful reagent for generating organobromine compounds. Certain ethers are cleaved with HBr. It also catalyzes alkylation reactions and the extraction of certain ores. Industrially significant organic compounds prepared from hydrobromic acid include allyl bromide, tetrabromobis(phenol), and bromoacetic acid.^[1] doi:10.1002/14356007.a04_405.

Syntheses

Hydrobromic acid can be prepared in the laboratory via the reaction of Br₂, SO₂, and water.^[2] More typically laboratory preparations involve the production of anhydrous HBr, which is then dissolved in water.

Hydrobromic acid has commonly been prepared industrially by reacting bromine with either sulfur or phosphorus and water. However, it can also be produced electrolytically.^[2]. It can also be prepared by treating bromides with non-oxidising acids like phosphoric or acetic acids.

Hydrobromic acid is available commercially in various concentrations and purities.

References

1. ^ Michael J. Dagani, Henry J. Barda, Theodore J. Benya, David C. Sanders "Bromine Compounds" in Ullmann's Encyclopedia of Industrial Chemistry" Wiley-VCH, Weinheim, 2000.
2. ^ ^{a b} Scott, A. (1900). "Preparation of pure hydrobromic acid". J. Chem. Soc., Trans. 77: 648–650. doi:10.1039/ct9007700648. 

External links

• International Chemical Safety Card 0282
• NIOSH Pocket Guide to Chemical Hazards
• Carlin, W. W. U.S. Patent 4,147,601

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