Chloric acid
Chemical compound
From Wikipedia, the free encyclopedia
Chloric acid, HClO3, is an oxoacid of chlorine, and the formal precursor of chlorate salts. It is a strong acid and an oxidizing agent.
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| Names | |
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| Other names
Chloric(V) acid | |
| 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 |
Oxidant, Corrosive |
| GHS labelling:[citation needed] | |
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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).
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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:[citation needed]
- 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]