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Potassium bicarbonate



Potassium bicarbonate
IUPAC name potassium hydrogen carbonate
Other names potassium acid carbonate
Identifiers
CAS number 298-14-6
Properties
Molecular formula KHCO3
Molar mass 100.11 g/mol
Appearance colorless crystals or white powder
Density 2.17 g/cm3, solid
Melting point

decomposes 100°C-200°C

Solubility in water 32.2 g/100 ml (20°C)
Structure
Crystal structure monoclinic
Hazards
MSDS Potassium bicarbonate
Related Compounds
Related compounds potassium carbonate
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Potassium bicarbonate (also known as potassium hydrogen carbonate or potassium acid carbonate), is a colorless, odorless, slightly basic, salty substance. The compound is used as a source of carbon dioxide for leavening in baking, extinguishing fire in powder fire extinguishers, acting as a reagent, and a strong buffering agent in medications. The US Food and Drug Administration (FDA) recognizes potassium bicarbonate as "generally recognized as safe". It is used as a base in foods to regulate pH.

Additional recommended knowledge

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 phytotoxic effects on plants (potassium bicarbonate has widespread use in crops, especially for neutralizing acidic soil), although there is no evidence of human carcinogenicity, no adverse effects of overexposure, and no LD50.

Physically, potassium bicarbonate occurs as a crystal or a soft white granular powder. It has a CAS No [298-14-6]. It is manufactured by reacting potassium carbonate with carbon dioxide and water:

K2CO3 + CO2 + H2O → 2 KHCO3

Potassium bicarbonate is used as a fire suppression agent ("BC powder") in some dry powder fire extinguishers, as the principal component of the Purple-K powder. 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]

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

     
    This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Potassium_bicarbonate". A list of authors is available in Wikipedia.
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