Potassium carbonate

Potassium carbonate

Names
IUPAC name Potassium carbonate
Other names Carbonate of potash, dipotassium carbonate, sub-carbonate of potash, pearl ash, pearlash, potash, salt of tartar, salt of wormwood.
Identifiers
CAS Number	584-08-7 Y 6381-79-9 sesquihydrate Y
3D model ( JSmol )	Interactive image
ChEBI	CHEBI:131526 N
ChemSpider	10949 Y
ECHA InfoCard	100.008.665
E number	E501(i) (acidity regulators, ...)
PubChem CID	11430
RTECS number	TS7750000
UNII	BQN1B9B9HA Y L9300DKS8U (sesquihydrate) Y
CompTox Dashboard (EPA)	DTXSID2036245
InChI InChI=1S/CH2O3.2K/c2-1(3)4;;/h(H2,2,3,4);;/q;2*+1/p-2 Y Key: BWHMMNNQKKPAPP-UHFFFAOYSA-L Y InChI=1/CH2O3.2K/c2-1(3)4;;/h(H2,2,3,4);;/q;2*+1/p-2 Key: BWHMMNNQKKPAPP-NUQVWONBAS
SMILES C(=O)([O-])[O-].[K+].[K+]
Properties
Chemical formula	K2CO3
Molar mass	138.205 g·mol−1
Appearance	White, hygroscopic solid
Density	2.43 g/cm3
Melting point	891 °C (1,636 °F; 1,164 K)
Boiling point	Decomposes
Solubility in water	110.3 g/(100 mL) (20 °C) 149.2 g/(100 mL) (100 °C)
Solubility	3.11 g/(100 mL) (25 °C) methanol Insoluble in alcohol, acetone
Acidity (pKa)	10.25
Magnetic susceptibility (χ)	−59.0·10−6 cm3/mol
Thermochemistry[1]
Heat capacity (C)	114.4 J/(mol·K)
Std molar entropy (S⦵298)	155.5 J/(mol·K)
Std enthalpy of formation (ΔfH⦵298)	−1151.0 kJ/mol
Gibbs free energy (ΔfG⦵)	−1063.5 kJ/mol
Enthalpy of fusion (ΔfH⦵fus)	27.6 kJ/mol
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H315, H319, H335
Precautionary statements	P261, P305+P351+P338
NFPA 704 (fire diamond)	2 0 0
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	1870 mg/kg (oral, rat)[2]
Safety data sheet (SDS)	ICSC 1588
Related compounds
Other anions	Potassium bicarbonate
Other cations	Lithium carbonate Sodium carbonate Rubidium carbonate Caesium carbonate
Related compounds	Ammonium carbonate Calcium carbonate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Potassium carbonate is the

Potassium carbonate is the primary component of potash and the more refined pearl ash or salt of tartar. Historically, pearl ash was created by baking potash in a kiln to remove impurities. The fine, white powder remaining was the pearl ash. The first patent issued by the US Patent Office was awarded to Samuel Hopkins in 1790 for an improved method of making potash and pearl ash.^[5]

In late 18th-century North America, before the development of baking powder, pearl ash was used as a leavening agent for quick breads.^[6][7]

The modern commercial production of potassium carbonate is by reaction of potassium hydroxide with carbon dioxide:^[3]

2 KOH + CO₂ → K₂CO₃ + H₂O

From the solution crystallizes the

2 KHCO₃ → K₂CO₃ + H₂O + CO₂

• (historically) for
  dishware production;^{[citation needed}
  ]
• as a dietary potassium supplement, containing 56% of elemental potassium,[8] in tablet or powder form to address low blood potassium levels caused by inadequate nourishment, nausea and vomiting, diarrhea, or potassium-depleting medications such as corticosteroids or diuretics;^[9][10]
• as a mild drying agent where other drying agents, such as calcium chloride and magnesium sulfate, may be incompatible. It is not suitable for acidic compounds, but can be useful for drying an organic phase if one has a small amount of acidic impurity. It may also be used to dry some ketones; alcohols, and amines prior to distillation.^[11]
• in
  hartshorn;^{[citation needed}
  ]
• in the
  aroma—the process of adding potassium carbonate to cocoa powder is usually called "Dutching" (and the products referred to as Dutch-processed cocoa powder), as the process was first developed in 1828 by Dutchman Coenraad Johannes van Houten;^{[citation needed}
  ]
• as a
  buffering agent in the production of mead or wine;^{[citation needed}
  ]
• in antique documents, it is reported to have been used to
  soften hard water;^[12]
• as a fire suppressant in
  deep-fat fryers and various other B class-related fires;^{[citation needed}
  ]
• in condensed aerosol fire suppression, although as the byproduct of potassium nitrate;^{[citation needed]}
• as an ingredient in welding fluxes, and in the flux coating on arc-welding rods;^{[citation needed]}
• as an
  farmed animals such as broiler breeder chickens;^{[citation needed}
  ]
• as an acidity regulator in Swedish snus snuff tobacco.^{[citation needed]}