Potassium bicarbonate
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| Names | |
|---|---|
| IUPAC name
potassium hydrogen carbonate
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| Other names
potassium acid carbonate
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| Identifiers | |
| ECHA InfoCard | 100.005.509 |
| EC Number |
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| E number | E501(ii) (acidity regulators, ...) |
PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| KHCO3 | |
| Molar mass | 100.115 g/mol |
| Appearance | white crystals |
| Odor | odorless |
| Density | 2.17 g/cm3 |
| Melting point | 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] |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-Flammable |
| Related compounds | |
Other anions
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Potassium carbonate |
Other cations
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Sodium bicarbonate Ammonium bicarbonate |
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 (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".[2]
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[citation needed] (potassium bicarbonate has widespread use in crops, especially for neutralizing acidic soil, and is also under consideration as an organic fungicide[3]), 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:
Potassium bicarbonate is very rarely found in its natural form, the mineral called kalicinite.
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 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.[4] [5]
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
- ^ 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. p. 7–13. ISBN 9780849305955. 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.
- ^ http://attra.ncat.org/attra-pub/bakingsoda.html
- ^ Powdery Mildew - Sustainable Gardening Australia
- ^ Organic Fruit Production in Michigan