Chemistry:Monopotassium arsenate

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Monopotassium arsenate
KH2AsO4.svg
Names
IUPAC name
Potassium dihydrogen arsorate
Other names
Macquer's salt
Identifiers
3D model (JSmol)
ChemSpider
EC Number
  • 232-065-8
UNII
UN number 1677
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 pictograms GHS06: ToxicGHS08: Health hazardGHS09: Environmental hazard
GHS Signal word Danger
H301, H331, H350, H410
P201, P202, P261, P264, P270, P271, P273, P281, P301+310, P304+340, P308+313, P311, P321, P330, P391, P403+233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
Tracking categories (test):

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]

Relevant acid-base equilibria for aqueous solutions of this diprotic acid derived from arsenic acid are as follows:

H3AsO4 + H2O ⇌ H2AsO4 + H3O+  (pKa1 = 2.19)
H2AsO4 + H2O ⇌ HAsO2−4 + H3O+  (pKa2 = 6.94)

Related compounds

References