Bromous acid
| Names | |
|---|---|
| IUPAC name
Bromous acid
| |
| Other names
Hydroxy-λ3-bromanone
Hydroxidooxidobromine | |
| Properties | |
| HBrO2 | |
| Molar mass | 112.911 g/mol |
| Appearance | Unstable yellowish solution |
| Odor | Bromine-like, suffocating |
| Melting point | Decomposes |
| Boiling point | Decomposes |
| Miscible | |
| Solubility | Reacts with bases |
| Acidity (pKa) | 3.43-6.25 (est.) |
| Thermochemistry | |
| Std enthalpy of
formation (ΔfH |
-72 kJ/mol[1] |
| Hazards | |
| Safety data sheet | None |
| Flash point | Non-flammable |
| Related compounds | |
| Related compounds
|
Hydrobromic acid Hypobromous acid Bromic acid Perbromic acid Chlorous acid Iodic acid |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Bromous acid is the inorganic compound with the formula of HBrO2. It is an unstable compound, although salts of its conjugate base, bromites, have been isolated. In acidic solution, bromites decompose to bromine.
Contents
Properties
Chemical
Bromous acid is unstable and will rapidly decompose in aq. solution to hypobromite and bromate.[3]
Addition of hydrogen peroxide to bromous acid will produce hypobromous acid, oxygen and water:[4]
- HBrO2 + H2O2 → HBrO + H2O + O2
Bromites reduce permanganates to manganates:
- 2 MnO−
4 + BrO−
2 + OH− → 2 MnO2−
4 + BrO−
3 + H2O
Physical
Due to its instability, the compound is poorly characterized, thus any properties of the compound are derived from its dilute solution.
Availability
Bromous acid is unstable and thus it is not commercially available.
Preparation
Addition of an acid to bromite salts will yield bromous acid, which is unstable and will rapidly decompose.
Addition of elemental bromine to a solution of silver nitrate will yield hypobromous acid which is further oxidized to bromous acid:[5]
- Br2 + AgNO3 + H2O → HBrO + AgBr + HNO3
- 2 AgNO3 + HBrO + Br2 + H2O → HBrO2 + 2 AgBr + 2 HNO3
Oxidizing hypobromous acid with hypochlorous acid will alos produce bromous acid as well as hydrochloric acid:
- HBrO + HClO → HBrO2 + HCl
A redox reaction of hypobromous acid can form bromous acid as its product:
- HBrO + H2O − 2e− → HBrO2 + 2H+
The disproportionation reaction of two equivalents hypobromous acid results in the formation of both bromous acid and hydrobromic acid:
- 2 HBrO → HBrO2 + HBr
A rearrangement reaction, which results from the syn-proportion of bromic acid and hydrobromic acid gives pure bromous acid:
- 2 HBrO3 + HBr → 3 HBrO2
Projects
- Make bromite salts
- Chemical demonstrations
- Belousov–Zhabotinsky reaction
Handling
Safety
Bromous acid is unstable and corrosive.
Storage
Cannot be stored due to its instability.
Disposal
Thiosulfates, sulfites, metabisulfites can be used to neutralize the compound to bromide.
References
- ↑ Kshirsagar, Girish; Field, Richard J.; Journal of Physical Chemistry; vol. 92; nb. 25; (1988); p. 7074 - 7079
- ↑ Field, Richard J.; Foersterling, Horst-Dieter; Journal of Physical Chemistry; vol. 90; nb. 21; (1986); p. 5400 - 5407
- ↑ Ariese, Freek; Ungvarai-Nagy, Zsuzsanna; Journal of Physical Chemistry; vol. 90; nb. 1; (1986); p. 1 - 4
- ↑ Bray, W. C.; Davis, P. R.; Journal of the American Chemical Society; vol. 52; (1930); p. 1427
- ↑ Richards, A. H.; Journal of the Society of Chemical Industry, London; vol. 25; (1906); p. 4
