Potassium bicarbonate
Potassium bicarbonate
IUPAC name
potassium hydrogencarbonate
Other names
potassium hydrogencarbonate, potassium acid carbonate
3D model (JSmol)
ECHA InfoCard 100.005.509 Edit this at Wikidata
EC Number
  • 206-059-0
E number E501(ii) (acidity regulators, ...)
  • InChI=1S/CH2O3.K/c2-1(3)4;/h(H2,2,3,4);/q;+1/p-1 checkY
  • InChI=1/CH2O3.K/c2-1(3)4;/h(H2,2,3,4);/q;+1/p-1
  • [K+].[O-]C(=O)O
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)
22.4 g/100 mL (20 °C)[1]
Solubility practically insoluble in alcohol
Acidity (pKa) 10.329[2]

6.351 (carbonic acid)[2]

-963.2 kJ/mol
A12BA04 (WHO)
GHS labelling:
GHS07: Exclamation mark
H315, H319, H335
P261, P264, P280, P302+P352, P304+P340, P305+P351+P338, P312, P332+P313, P362, P403+P233, P405
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
Flash point Non-Flammable
Lethal dose or concentration (LD, LC):
> 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).
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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

Production and reactivity

It is manufactured by treating an aqueous solution of potassium carbonate 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.


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]


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 14 cup per gallon.[16]


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]


  1. ^ a b c H. Schultz; G. Bauer; E. Schachl; F. Hagedorn; P. Schmittinger (2005). "Potassium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a22_039. ISBN 3-527-30673-0.
  2. ^ a b Goldberg, Robert N.; Kishore, Nand; Lennen, Rebecca M. (2003). "Thermodynamic quantities for the ionization reactions of buffers in water". In David R. Lide (ed.). CRC handbook of chemistry and physics (84th ed.). Boca Raton, FL: CRC Press. pp. 7–13. ISBN 978-0-8493-0595-5. Retrieved 6 March 2011.
  3. ^ "Potassium bicarbonate". pubchem.ncbi.nlm.nih.gov.
  4. ^ "Potassium Bicarbonate". encyclopedia.com. Cengage. Retrieved May 29, 2020.
  5. ^ "Home cooking with less salt". harvard.edu. Harvard University. March 2020. Retrieved May 29, 2020.
  6. ^ Wilkens, Katy G. (15 December 2018). "You Have the (Baking) Power with Low-Sodium Baking Powders". agingkingcounty.org. Aging & Disability Services for Seattle & King County. Retrieved May 29, 2020.
  7. ^ "Why Your Bottled Water Contains Four Different Ingredients". Time Magazine. July 24, 2014.
  8. ^ He FJ, MacGregor GA (2008). "Beneficial effects of potassium on human health". Physiologia Plantarum. 133 (4): 725–735. doi:10.1111/j.1399-3054.2007.01033.x. PMID 18724413.
  9. ^ Vinceti M, Filippini T, Orsini N (2016). "Meta-Analysis of Potassium Intake and the Risk of Stroke". Journal of the American Heart Association. 5 (10): e004210. doi:10.1161/JAHA.116.004210. PMC 5121516. PMID 27792643.
  10. ^ "Purple-K-Powder". US Naval Research Laboratory. Archived from the original on 15 February 2009. Retrieved 8 February 2012.
  11. ^ "Potassium Bicarbonate Handbook" (PDF). Armand Products Company. Archived from the original (PDF) on 2021-01-22. Retrieved 2016-09-06.
  12. ^ "Use of Baking Soda as a Fungicide". Archived from the original on 2010-05-07. Retrieved 2010-02-14.
  13. ^ "Powdery Mildew - Sustainable Gardening Australia". Archived from the original on 2016-03-03.
  14. ^ "Organic Fruit Production in Michigan".
  15. ^ "Efficacy of Armicarb (potassium bicarbonate) against scab and sooty blotch on apples" (PDF).
  16. ^ "How to Toss Your Spanish Moss". SkyFrog landscape company. 4 December 2020.
  17. ^ "saleratus". merriam-webster.com. Merriam-Webster. Retrieved May 29, 2020.