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Chloric acid

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Chloric acid
Chloric acid
Chloric acid
Names
Other names
Chloric(V) acid
Identifiers
ECHA InfoCard 100.029.303 Edit this at Wikidata
Properties
HClO3
Molar mass 84.45914 g mol−1
Appearance colourless solution
Density 1 g/mL, solution (approximate)
>40 g/100 ml (20 °C)
Acidity (pKa) ca. −1
Structure
pyramidal
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Oxidant
Related compounds
Other anions
bromic acid
iodic acid
Other cations
ammonium chlorate
sodium chlorate
potassium chlorate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Chloric acid, HClO3, is an oxoacid of chlorine, and the formal precursor of chlorate salts. It is a strong acid (pKa ≈ −1) and oxidizing agent.

It is prepared by the reaction of sulfuric acid with barium chlorate, the insoluble barium sulfate being removed by precipitation:

Ba(ClO3)2 + H2SO4 → 2HClO3 + BaSO4

Another method is the heating of hypochlorous acid, of which productions include chloric acid and hydrogen chloride:

3HClO → HClO3 + 2 HCl

It is stable in cold aqueous solution up to a concentration of approximately 30%, and solution of up to 40% can be prepared by careful evaporation under reduced pressure. Above these concentrations, and on warming, chloric acid solutions decompose to give a variety of products, for example:

8HClO3 → 4HClO4 + 2H2O + 2Cl2 + 3 O2
3HClO3 → HClO4 + H2O + 2 ClO2

The decomposition is controlled by kinetic factors: indeed, chloric acid is never thermodynamically stable with respect to disproportionation.

See also

References

  • Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  • King, R. B. (Ed.) (1994) Encyclopedia of Inorganic Chemistry, Vol. 2, p. 658. Chichester:Wiley. ISBN 0-471-93620-0