Potassium bicarbonate

Chembox new
Name = Potassium bicarbonate
ImageFile = Potassium bicarbonate.jpg
ImageSize = 200px
ImageName = Potassium bicarbonate
IUPACName = potassium hydrogen carbonate
OtherNames = potassium acid carbonate
Section1 = Chembox Identifiers
CASNo = 298-14-6
Section2 = Chembox Properties
Formula = KHCO₃
MolarMass = 100.11 g/mol
Appearance = colorless crystals or white powder
Density = 2.17 g/cm³, solid
Solubility = 32.2 g/100 ml (20°C)
MeltingPt = decomposes 100°C-200°C
Section3 = Chembox Structure
CrystalStruct = monoclinic
Section7 = Chembox Hazards
ExternalMSDS = [http://msds.ehs.cornell.edu/msds/msdsdod/a495/m247034.htm Potassium bicarbonate]
Section8 = Chembox Related
OtherCpds = potassium carbonate

Potassium bicarbonate (also known as potassium hydrogen carbonate or potassium acid carbonate), is a colorless, odorless, slightly basic, salty substance. The US Food and Drug Administration (FDA) recognizes potassium bicarbonate as "generally recognized as safe".

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 plantsFact|date=April 2008 (potassium bicarbonate has widespread use in crops, especially for neutralizing acidic soil, and is also under consideration as an organic fungicide [FiBL (2006) [http://www.fibl.org/english/news/opinion-papers/2006/0811-bicarbonate.php Use of potassium bicarbonate as a fungicide in organic farming] ] ), 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 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 very rarely found in its natural form, mineral called kalicinite.

Uses

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.

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 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. [http://www.nrl.navy.mil/content.php?P=PURPLEK]

Potassium bicarbonate is an effective fungicide against powdery mildew. [ [http://www.sgaonline.org.au/info_powderymildew.html Powdery Mildew - Sustainable Gardening Australia ] ]

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

External links

* [http://www.armandproducts.com/pdfs/PotBiVs6.PDF Potassium Bicarbonate Handbook]
* [http://www.omri.org/Potassium_bicarbonate_crops.pdf Potassium Bicarbonate: Crops]