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]
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IUPAC name Selenous acid
Selenic(IV) acid
Other names Selenious acid
Identifiers
CAS number 7783-00-8
PubChem 1091
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 you.

Related pages

Sources

  1. Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, Florida: CRC Press. pp. 4–81. ISBN 0-8493-0594-2.
  2. Ka and pKa for Polyprotic Acids. ucdsb.on.ca