Chloric acid
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| Names | |
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| Other names
Chloric(V) acid
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.029.303 |
| EC Number |
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PubChem CID
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| UNII | |
| UN number | 2626 |
CompTox Dashboard (EPA)
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| Properties | |
| HClO3 | |
| Molar mass | 84.46 g·mol−1 |
| Appearance | colourless solution |
| Density | 1 g/mL, solution (approximate) |
| >40 g/100ml (20 °C (68 °F; 293 K)) | |
| Acidity (pKa) | −2.7[1] |
| Conjugate base | Chlorate |
| Structure | |
| pyramidal | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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Oxidant, Corrosive |
| GHS labelling: | |
 
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| Danger | |
| H271, H314 | |
| P210, P220, P221, P260, P264, P280, P283, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P306+P360, P310, P321, P363, P370+P378, P371+P380+P375, P405, P501 | |
| NFPA 704 (fire diamond) | |
| Related compounds | |
Other anions
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Other cations
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Related compounds
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
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Chloric acid, HClO3, is an oxoacid of chlorine, and the formal precursor of chlorate salts. It is a strong acid and an oxidizing agent.
Properties
Chloric acid is thermodynamically unstable with respect to disproportionation.
Chloric acid 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.[2] Above these concentrations, chloric acid solutions decompose to give a variety of products, for example:[2]
- 8 HClO3 → 4 HClO4 + 2 H2O + 2 Cl2 + 3 O2
- 3 HClO3 → HClO4 + H2O + 2 ClO2
When it reacts with suitable cations, it forms chlorate (ClO3) salts.
Production
Chloric acid may be produced from barium chlorate through its reaction with sulfuric acid, resulting in a solution of chloric acid and insoluble barium sulfate precipitate:[3]
- Ba(ClO3)2 + H2SO4 → 2 HClO3 + BaSO4
The chlorate must be dissolved in boiling water and the acid should be somewhat diluted in water and heated before mixing.
Another method which can be used to produce solutions up to 10% concentration is by the use of cation exchange resins and a soluble salt such as NaClO3, where the Na+ cation will exchange with H+.[3]
Another method is the heating of hypochlorous acid, producing chloric acid and hydrogen chloride:
- 3 HClO → HClO3 + 2 HCl
The acid may be concentrated up to 40% in a vacuum dessicator over H2SO4.[3]
Hazards
Chloric acid is a powerful oxidizing agent which ignites most organic materials on contact. It is also corrosive.[4]
See also
- Chlorate
- Hypochlorous acid
- Chlorous acid
- Perchloric acid
- Oxidizing acid
- Dichlorine pentoxide
References
- ^ Holleman, Arnold Frederik; Wiberg, Egon (2001), Wiberg, Nils (ed.), Inorganic Chemistry, translated by Eagleson, Mary; Brewer, William, San Diego/Berlin: Academic Press/De Gruyter, ISBN 0-12-352651-5
- ^ a b Mendiratta, Sudhir K.; Duncan, Budd L. (2003), "Chloric Acid and Chlorates", Kirk-Othmer Encyclopedia of Chemical Technology (5th ed.), New York: John Wiley, doi:10.1002/0471238961.0308121513051404.a01.pub2, ISBN 9780471238966
- ^ a b c Schmeisser, M. "5. Chlorine, Bromine, Iodine". In Brauer, Georg; Riley, Reed F. (eds.). Handbook of Preparative Inorganic Chemistry (2nd ed.). New York, London: Academic Press. pp. 312–313. ISBN 9780121266011. Retrieved 6 December 2024.
- ^ "Chloric acid". PubChem. National Institute of Health.
Additional Information
- Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. doi:10.1016/C2009-0-30414-6. ISBN 978-0-08-037941-8.
- R. Bruce King, ed. (1994). "Chloric acid". Encyclopedia of Inorganic Chemistry. Vol. 2. Chichester: Wiley. p. 658. ISBN 0-471-93620-0.