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Potassium bicarbonate: Wikis


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Potassium bicarbonate
Potassium bicarbonate
IUPAC name
Other names potassium acid carbonate
CAS number 298-14-6
PubChem 516893
EC number 206-059-0
Molecular formula KHCO3
Molar mass 100.115 g/mol
Appearance white crystals
Odor odorless
Density 2.17 g/cm3
Melting point

292 °C

Solubility in water 22.49 g/100 mL (20 °C)
60 g/100 mL (60 °C)
Solubility practically insoluble in alcohol
Acidity (pKa) 8.2 (0.1M)
EU Index Not listed
NFPA 704
NFPA 704.svg
Flash point Non-Flammable
Related compounds
Other anions Potassium carbonate
Other cations Sodium bicarbonate
Ammonium bicarbonate
Related compounds Potassium bisulfate
Potassium hydrogen phosphate
 Yes check.svgY (what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
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 US Food and Drug Administration (FDA), potassium bicarbonate is "generally recognized as safe".

Potassium bicarbonate is soluble in water, and is often found added to bottled water to affect taste; however, it is not soluble in alcohol. Decomposition of the substance occurs between 100 °C and 120 °C into K2CO3 (potassium carbonate), H2O (water), and CO2 (carbon dioxide). In concentrations greater than 0.5%, KHCO3 can have toxic effects on plants (potassium bicarbonate has widespread use in crops, especially for neutralizing acidic soil, and is also under consideration as an organic fungicide[1]), although there is no evidence of human carcinogenicity, no adverse effects of overexposure, and an undetermined LD50.

Physically, potassium bicarbonate occurs as a crystal or a soft white granular powder. It is manufactured by reacting potassium carbonate with carbon dioxide and water:

K2CO3 + CO2 + H2O → 2 KHCO3

Potassium bicarbonate is very rarely found in its natural form, the mineral called kalicinite.

A fire extinguisher containing potassium bicarbonate.



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 a base in foods 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. It is the only dry chemical fire suppression agent recognized by the National Fire Protection Association for firefighting at airport crash rescue sites. It is about twice as effective in fire suppression as sodium bicarbonate. [1]

Potassium bicarbonate is an effective fungicide against powdery mildew, allowed for use in organic farming.[2] [3]


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.


  1. ^ FiBL (2006) Use of potassium bicarbonate as a fungicide in organic farming
  2. ^ Powdery Mildew - Sustainable Gardening Australia
  3. ^ Organic Fruit Production in Michigan

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