Formula H2TeO3 Appearance colorless crystals | Molar mass 177.616 g/mol Pubchem 24936 | |
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Tellurous acid is an inorganic compound with the formula H2TeO3. It is the oxoacid of tellurium(IV). The compound is not well characterized. An alternative way of writing its formula is (HO)2TeO. In principle, tellurous acid would form by treatment of tellurium dioxide with water, i.e. hydrolysis. The related conjugate base is well known in the form of several salts such as potassium acid tellurite, KHTeO3.
Properties
In contrast to the analogous compound Selenous acid, Tellurous acid is only metastable. Most tellurite salts contain the TeO2−
3 ion. Oxidation of its aqueous solution with hydrogen peroxide gives the tellurate ion. It is usually prepared as an aqueous solution where it acts as a weak acid.
3 Ka1 = 2 x 10−3 HTeO−
3 + H2O ⇄ H3O+ + TeO2−
3 Ka2 = 1 x 10−8
References
Tellurous acid Wikipedia(Text) CC BY-SA