Potassium bicarbonate

Not to be confused with Sodium bicarbonate.

Potassium bicarbonate

Potassium bicarbonate
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Names
IUPAC name potassium hydrogen carbonate
Other names potassium acid carbonate
Identifiers
CAS Number	298-14-6 Y
ChEBI	CHEBI:81862 N
ChemSpider	55053 Y
EC Number	206-059-0
Jmol 3D model	Interactive image
PubChem	516893
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	33.7 g/100 mL (20 °C) 60 g/100 mL (60 °C)
Solubility	practically insoluble in alcohol
Acidity (pKa)	10.329 6.351 (carbonic acid)
Thermochemistry
Std enthalpy of formation (ΔfHo298)	-963.2 kJ/mol
Pharmacology
ATC code	A12BA04
Vapor pressure	{{{value}}}
Related compounds
Other anions	Potassium carbonate
Other cations	Sodium bicarbonate Ammonium bicarbonate
Related compounds	Potassium bisulfate Potassium hydrogen 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

Potassium bicarbonate (also known as potassium hydrogen carbonate or potassium acid carbonate) is a colorless, odorless, slightly basic, salty substance. According to the U.S. Food and Drug Administration (FDA), potassium bicarbonate is "generally recognized as safe". There is no evidence of human carcinogenicity, no adverse effects of overexposure, and an undetermined LD₅₀. It is among the food additives encoded by European Union, identified by the initials E 501. Physically, potassium bicarbonate occurs as a crystal or a soft white granular powder. Potassium bicarbonate is very rarely found in its natural form, the mineral called kalicinite.

A fire extinguisher containing potassium bicarbonate.

Chemistry

Decomposition of the bicarbonate occurs between 100 °C and 120 °C:

2 KHCO₃ → K₂CO₃ + CO₂ + H₂O

It is manufactured by reversing the above: reaction of potassium carbonate with carbon dioxide and water.

K₂CO₃ + CO₂ + H₂O → 2 KHCO₃

Uses

The compound is used as a source of carbon dioxide for leavening in baking, extinguishing fire in dry chemical fire extinguishers, acting as a reagent, and a strong buffering agent in medications.

It is used as an additive in winemaking and as a base in foods and to regulate pH. It is a common ingredient in club soda, where it is used to soften the effect of effervescence.

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.

Potassium bicarbonate is an effective fungicide against powdery mildew and apple scab, allowed for use in organic farming.

Potassium bicarbonate is often found added to bottled water to affect taste.

Potassium bicarbonate has widespread use in crops, especially for neutralizing acidic soil

Some Africans use it as a native salt in cooking.

History

The word saleratus, from Latin sal æratus meaning "aerated salt", was widely used in the 19th century for both potassium bicarbonate and sodium bicarbonate. The term has now fallen out of common usage.

External links

• Potassium Bicarbonate Handbook
• OMRI Potassium Bicarbonate