Potassium bicarbonate

Potassium bicarbonate
Names
IUPAC name
potassium hydrogen carbonate
Other names
potassium acid carbonate
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.005.509
EC Number 206-059-0
Properties
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)
33.7 g/100 mL (20 °C)
60 g/100 mL (60 °C)
Solubility practically insoluble in alcohol
Acidity (pKa) 10.329[1]

6.351 (carbonic acid)[1]

Thermochemistry
-963.2 kJ/mol
Pharmacology
A12BA04 (WHO)
Hazards
Safety data sheet MSDS
R-phrases (outdated) R36 R37 R38
NFPA 704
Flammability code 0: Will not burn. E.g., waterHealth code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
0
1
0
Flash point Non-Flammable
Lethal dose or concentration (LD, LC):
> 2000 mg/kg (rat, oral)
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).
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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".[2] 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 E number E501. 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 and 120 °C (212 and 248 °F):

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

This compound is 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.

Potassium bicarbonate is often found added to club soda to improve taste,[3] 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.[4]

Potassium bicarbonate is an effective fungicide against powdery mildew and apple scab, allowed for use in organic farming.[5][6][7][8]

Potassium bicarbonate has widespread use in crops, especially for neutralizing acidic soil.[9]

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.

References

  1. 1 2 Goldberg, Robert N.; Kishore, Nand; Lennen, Rebecca M. (2003). "Thermodynamic quantities for the ionization reactions of buffers in water". In David R. Lide. 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.
  2. ↑ GRAS Notification Program (October 31, 2006). "Potassium bicarbonate". GRAS Substances (SCOGS) Database. US FDA. Archived from the original on March 5, 2011. Retrieved March 5, 2011.
  3. ↑ "Why Your Bottled Water Contains Four Different Ingredients". Time Magazine.
  4. ↑ "Purple-K-Powder". US Naval Research Laboratory. Retrieved 8 February 2012.
  5. ↑ "Use of Baking Soda as a Fungicide".
  6. ↑ "Powdery Mildew - Sustainable Gardening Australia". Archived from the original on 2016-03-03.
  7. ↑ "Organic Fruit Production in Michigan".
  8. ↑ "Efficacy of Armicarb (potassium bicarbonate) against scab and sooty blotch on apples" (PDF).
  9. ↑ "Potassium Bicarbonate Handbook" (PDF). Armand Products Company.
  • Potassium Bicarbonate Handbook
  • OMRI Potassium Bicarbonate
  • Safety Data sheet - potassium bicarbonate
  •  "Saleratus". New International Encyclopedia. 1905.
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