Hydrobromic acid

Hydrobromic acid
Identifiers
CAS number 10035-10-6 Y
ChemSpider 255 Y
EC number 233-113-0
ChEBI CHEBI:47266 Y
RTECS number MW3850000
Jmol-3D images Image 1
Properties
Molecular formula HBr
Molar mass N/A
Appearance colorless liquid
Density 1.49 g/cm3 (48% w/w aq.)
Melting point

-11 °C (47–49% w/w aq.)
Boiling point

122 °C at 700 mmHg (47–49% w/w aq.)
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 (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Hydrobromic acid (HBr) 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 stronger acid than hydrochloric acid, but not as strong as hydroiodic acid. Hydrobromic acid is one of the strongest mineral acids known.

Contents

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]

Syntheses

Hydrobromic acid can be prepared in the laboratory via the reaction of Br2, SO2, and water.[2]

Br2 + SO2 + 2 H2O → H2SO4 + 2 HBr

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. doi:10.1002/14356007.a04_405
  2. ^ a b Scott, A. (1900). "Preparation of pure hydrobromic acid". J. Chem. Soc., Trans. 77: 648–650. doi:10.1039/ct9007700648. 

External links

Media related to [//commons.wikimedia.org/wiki/Category:Hydrogen_bromide Hydrogen bromide] at Wikimedia Commons