Hydrobromic acid
| Hydrobromic acid | ||
|---|---|---|
| Identifiers | ||
| CAS number | 10035-10-6  | |
| PubChem | 260 | |
| ChemSpider | 255 | |
| EC number | 233-113-0 | |
| ChEBI | CHEBI:47266 | |
| RTECS number | MW3850000 | |
| Jmol-3D images | Image 1 | |
| ||
| ||
| Properties | ||
| Molecular formula | HBr | |
| Molar mass | 80.91 | |
| Appearance | colorless/faint yellow liquid | |
| Odor | acrid | |
| 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 | 221 g/100 mL (0 °C) 204 g/100 mL (15 °C) 130 g/100 mL (100 °C) | |
| Acidity (pKa) | −9[1] | |
| Viscosity | 0.84 cP (-75 °C) | |
| Thermochemistry | ||
| Std enthalpy of formation ΔfH |
-36.3 kJ/mol | |
| Standard molar entropy S |
198.7 J/K mol | |
| Specific heat capacity, C | 29.1 J/K mol | |
| 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 | |
(verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | ||
| Infobox references | ||
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 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.
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.[2]
Syntheses
Hydrobromic acid can be prepared in the laboratory via the reaction of Br2, SO2, and water.[3]
- 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.[3] 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
- ↑ Bell, R.P. The Proton in Chemistry, 2nd ed., Cornell University Press, Ithaca, NY, 1973.
- ↑ Dagani, M. J.; Barda, H. J.; Benya, T. J.; Sanders, D. C. (2005), "Bromine Compounds", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a04_405
- ↑ 3.0 3.1 Scott, A. (1900). "Preparation of Pure Hydrobromic Acid". Journal of the Chemical Society, Transactions 77: 648–651. doi:10.1039/ct9007700648.
External links
Media related to Hydrogen bromide at Wikimedia Commons
- International Chemical Safety Card 0282
- NIOSH Pocket Guide to Chemical Hazards
- Carlin, W. W. U.S. Patent 4,147,601