Hydroxide



Hydroxide
IUPAC name hydroxide
Systematic name hydroxide
oxidanide
hydridooxygenate(1−)
Identifiers
CAS number 14280-30-9
PubChem 961
SMILES [OH-]
InChI InChI=1/H2O/h1H2/
p-1/fHO/h1h/q-1
Properties
Molecular formula H−
Molar mass 17.00274 (7) g/mol
Acidity (pKa) ~22
Basicity (pKb) -1.74
15.74
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

In base. It is one of the simplest diatomic ions known.

Inorganic compounds that contain the hydroxyl group are referred to as hydroxides. Common hydroxides include:

Hydroxide as a base

Most compounds containing hydroxide are bases.

An ammonia, NH3:

NH3(g) + H2O(l) ⇌ NH4+(aq) + OH−(aq)

Thus, hydroxide ions are heavily involved in neutralization.

Salts containing hydroxide are called base salts. Base salts will dissociate into a cation and one or more hydroxide ions in water, making the solution basic. Base salts will undergo neutralisation reactions with acids. In general acid-alkali reactions can be simplified to

OH−(aq) + (l)

by omitting spectator ions.

Solubility

Most inorganic hydroxide salts are insoluble in water, except for those with cations from Tl+.

Applications

Hydroxides and hydroxide ions are relatively common. Many useful chemicals and chemical processes involve hydroxides or hydroxide ions. bauxite is composed largely of aluminium hydroxides.

Ligand

The hydroxide ion is a kind of lone pairs of electrons, behaving as a Lewis base. Examples of complexes containing such a ligand include the aluminate ion [Al(OH)4]− and aurate ion [Au(OH)4]−.

See also

Notes

  • Solvation and Transport of H3O+ and OH− Ions in Water (JCP 99, 5749 (1995)
     
    This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Hydroxide". A list of authors is available in Wikipedia.