Monopotassium arsenate is the inorganic compound with the formula KH2AsO4. A white solid, this salt is used to prepared other arsenic-containing compounds, mainly pesticides. It is prepared by calcining arsenic oxide and potassium nitrate, followed by extraction with water.[1]
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| Names | |
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| IUPAC name
Potassium dihydrogen arsorate
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| Other names
Macquer's salt
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.029.150 |
| EC Number |
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PubChem CID
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| UNII | |
| UN number | 1677 |
CompTox Dashboard (EPA)
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| Properties | |
| AsH2KO4 | |
| Molar mass | 180.032 g·mol−1 |
| Appearance | white solid |
| Density | 2.867 g/cm3 |
| Melting point | 288 °C (550 °F; 561 K) |
| Hazards | |
| GHS labelling: | |
  
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| Danger | |
| H301, H331, H350, H410 | |
| P201, P202, P261, P264, P270, P271, P273, P281, P301+P310, P304+P340, P308+P313, P311, P321, P330, P391, P403+P233, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Relevant acid-base equilibria for aqueous solutions of this diprotic acid derived from arsenic acid are as follows:
- H3AsO4 + H2O ⇌ H
2AsO−
4 + H3O+ (pKa1 = 2.19) - H
2AsO−
4 + H2O ⇌ HAsO2−
4 + H3O+ (pKa2 = 6.94)
Related compounds
edit- Trisodium arsenate, Na3AsO4
- Disodium hydrogen arsenate, Na2HAsO4
References
edit- ^ Grund, S. C.; Hanusch, K.; Wolf, H. U. "Arsenic and Arsenic Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a03_113.pub2. ISBN 978-3527306732.
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