Potassium carbonate

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Carbonate of potash redirects here. For one of potassium carbonate's impure forms, see potash.

Potassium carbonate

General
Other names	Potash, pearlash
Molecular formula	K₂CO₃
Molar mass	138.2055 g/mol
Appearance	white solid, deliquescent
CAS number	[584-08-7]
Properties
Density and phase	2.29 g/cm³, solid
Solubility in water	112 g/100 ml (20 °C)
Other solvents e.g. ethanol, acetone	Poorly soluble in most organic solvents including ethanol
Melting point	891 °C
Boiling point	decomposes
Basicity (pK_a)	pH: 11.6 Aqueous solution
Structure
Coordination geometry	?
Crystal structure	?
Thermodynamic data
Std enthalpy change of formation, Δ_fH^o_solid	−1151 kJ/mol
Std molar entropy, S^o_solid	156 J·K⁻¹·mol⁻¹
Hazards
MSDS	External MSDS
EU classification	not listed
NFPA 704	0 2 0
Flash point	non flammable
RTECS number	TS7750000
Supplementary data page
Structure and properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Other anions	Potassium bicarbonate
Other cations	Lithium carbonate Sodium carbonate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Potassium carbonate is a white salt, soluble in water (insoluble in alcohol), which forms a strongly alkaline solution. It can be made as the product of potassium hydroxide's absorbent reaction with carbon dioxide. It is deliquescent, often appearing a damp or wet solid. Potassium carbonate is used in the production of soap and glass.

1 History
2 Production
3 Applications
4 References
5 External links

[edit] History

Potassium carbonate was first identified in 1742 by Antonio Campanella and is the primary component of potash and the more refined pearlash or salts of tartar. Historically pearlash was created by baking potash in a kiln to remove impurities. The fine white powder remaining was the pearlash. The first patent issued by the U.S. Patent Office was awarded to Samuel Hopkins in 1790 for an improved method of making pearlash.

In late 18th century North America, before the development of baking powder, pearlash began to be used as a leavening agent in "quick breads".

Other terms for potassium carbonate include:

Carbonate of potash
Dipotassium carbonate
Dipotassium salt
Pearl ash
Potash
Salt of tartar
Salt of wormwood

[edit] Production

Today potassium carbonate is prepared commercially by the electrolysis of potassium chloride. The resulting potassium hydroxide is then carbonated using carbon dioxide to form potassium carbonate, which is often used to produce other potassium compounds. CO2 + 2KOH --> K2CO3 + H2O

[edit] Applications

Pearlash has been used for soap, glass, and china production.

In the laboratory, it may be used as a mild drying agent where other drying agents such as calcium chloride may be incompatible. However, it is not suitable for acidic compounds.