potassium hydrogen carbonate
potassium acid carbonate
|Molar mass||100.115 g/mol|
|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|
6.351 (carbonic acid)
Std enthalpy of
|EU Index||Not listed|
|R-phrases||R36 R37 R38|
LD50 (Median lethal dose)
|> 2000 mg/kg (rat, oral)|
Potassium hydrogen phosphate
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
|what is: / ?)(|
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.
Decomposition of the bicarbonate occurs between 100 °C and 120 °C:
- K2CO3 + CO2 + H2O → 2 KHCO3
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 often found added to bottled water to affect taste. 
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.
- 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.
- 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.
- "Purple-K-Powder". US Naval Research Laboratory. Retrieved 8 February 2012.
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