Selenous acid
Selenous acid, also known as selenious acid, is a chemical compound. Its chemical formula is H2SeO3. It is an acid. It contains hydrogen and selenite ions.
| Selenous acid[1] | |
|---|---|
| |
| |
| IUPAC name | Selenous acid Selenic(IV) acid |
| Other names | Selenious acid |
| Identifiers | |
| CAS number | |
| PubChem | |
| KEGG | D05814 |
| ChEBI | CHEBI:26642 |
| SMILES | O[Se+]([O-])O |
| Properties | |
| Molecular formula | H2SeO3 |
| Molar mass | 128.97 g/mol |
| Appearance | white hygroscopic crystals |
| Density | 3.0 g/cm3 |
| Melting point |
decomposes at 70°C |
| Solubility in water | very soluble |
| Solubility | soluble in ethanol |
| Acidity (pKa) | 2.46, 7.3[2] |
| −45.4·10−6 cm3/mol | |
| Related compounds | |
| Other anions | selenic acid hydrogen selenide |
| Other cations | sodium selenite |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
Properties
Selenous acid is a weak acid. It can be heated to make selenium dioxide. It is more stable than sulfurous acid. It can be crystallized as a white solid. It is a weak oxidizing agent. It reacts with bases to make selenites.
Preparation
It is made by dissolving selenium dioxide in water.
Uses
It is used to dye steel a blue-grey color. It is used in the making of organic compounds.
Safety
Selenous acid is very toxic. Just ingesting a small amount can kill a person.
Related pages
Sources
- ↑ Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, Florida: CRC Press. pp. 4–81. ISBN 0-8493-0594-2.
- ↑ Ka and pKa for Polyprotic Acids. ucdsb.on.ca