Potassium bicarbonate

Not to be confused with Sodium bicarbonate.

Potassium bicarbonate (IUPAC name: potassium hydrogencarbonate, also known as potassium acid carbonate) is the inorganic compound with the chemical formula KHCO₃. It is a white solid.^[1]

A fire extinguisher containing potassium bicarbonate

Potassium bicarbonate

Potassium bicarbonate
Names
IUPAC name potassium hydrogencarbonate
Other names potassium hydrogencarbonate, potassium acid carbonate
Identifiers
CAS Number	298-14-6 Y
3D model (JSmol)	Interactive image
Beilstein Reference	4535309
ChEBI	CHEBI:81862 Y
ChEMBL	ChEMBL2106975
ChemSpider	55053 Y
DrugBank	DB11098
ECHA InfoCard	100.005.509
EC Number	206-059-0
E number	E501(ii) (acidity regulators, ...)
KEGG	C18606
PubChem CID	516893
UNII	HM5Z15LEBN Y
CompTox Dashboard (EPA)	DTXSID0021177
InChI InChI=1S/CH2O3.K/c2-1(3)4;/h(H2,2,3,4);/q;+1/p-1 Y Key: TYJJADVDDVDEDZ-UHFFFAOYSA-M Y InChI=1/CH2O3.K/c2-1(3)4;/h(H2,2,3,4);/q;+1/p-1 Key: TYJJADVDDVDEDZ-REWHXWOFAA
SMILES [K+].[O-]C(=O)O
Properties
Chemical formula	KHCO3
Molar mass	100.115 g/mol
Appearance	white crystals
Odor	odorless
Density	2.17 g/cm3
Melting point	292 °C (558 °F; 565 K) (decomposes)
Solubility in water	22.4 g/100 mL (20 °C)[1]
Solubility	practically insoluble in alcohol
Acidity (pKa)	10.329[2] 6.351 (carbonic acid)[2]
Thermochemistry
Std enthalpy of formation (ΔfH⦵298)	−963.2 kJ/mol
Pharmacology
ATC code	A12BA04 (WHO)
Hazards[3]
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P280, P302+P352, P304+P340, P305+P351+P338, P312, P332+P313, P362, P403+P233, P405
NFPA 704 (fire diamond)	1 0 0
Flash point	Non-Flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	> 2000 mg/kg (rat, oral)
Safety data sheet (SDS)	MSDS
Related compounds
Other anions	Potassium carbonate
Other cations	Sodium bicarbonate Ammonium bicarbonate
Related compounds	Potassium bisulfate Monopotassium phosphate Dipotassium phosphate
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

Production and reactivity

It is manufactured by treating an aqueous solution of potassium carbonate or potassium hydroxide with carbon dioxide:^[1]

K₂CO₃ + CO₂ + H₂O → 2 KHCO₃

Decomposition of the bicarbonate occurs between 100 and 120 °C (212 and 248 °F):

2 KHCO₃ → K₂CO₃ + CO₂ + H₂O

This reaction is employed to prepare high purity potassium carbonate.

Uses

Food and drink

This compound is a source of carbon dioxide for leavening in baking. It can substitute for baking soda (sodium bicarbonate) for those with a low-sodium diet,^[4] and it is an ingredient in low-sodium baking powders.^[5][6]

As an inexpensive, nontoxic base, it is widely used in diverse application to regulate pH or as a reagent. Examples include as buffering agent in medications, an additive in winemaking.

Potassium bicarbonate is often added to bottled water to improve taste,^[7] and is also used in club soda.

Medical uses and health

Higher potassium intake may prevent development of kidney stone disease.^[8] Higher potassium intake is associated with a reduced risk of stroke.^[9]

Fire extinguishers

Potassium bicarbonate is used as a fire suppression agent ("BC dry chemical") in some dry chemical fire extinguishers, as the principal component of the Purple-K dry chemical, and in some applications of condensed aerosol fire suppression. It is the only dry chemical fire suppression agent recognized by the U.S. National Fire Protection Association for firefighting at airport crash rescue sites. It is about twice as effective in fire suppression as sodium bicarbonate.^[10]

Agriculture

Potassium bicarbonate has widespread use in crops, especially for neutralizing acidic soil.^[11]

Potassium bicarbonate is an effective fungicide against powdery mildew and apple scab, allowed for use in organic farming.^{[12][13][14][15]}

Potassium bicarbonate is a contact killer for Spanish moss when mixed 1⁄4 cup per gallon.^[16]

History

The word saleratus, from Latin sal æratus meaning "aerated salt", first used in the nineteenth century, refers to both potassium bicarbonate and sodium bicarbonate.^[17]