https://www.sciencemadness.org/smwiki/index.php?title=Potassium_sulfite&feed=atom&action=history
Potassium sulfite - Revision history
2024-03-28T09:30:09Z
Revision history for this page on the wiki
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https://www.sciencemadness.org/smwiki/index.php?title=Potassium_sulfite&diff=7446&oldid=prev
Mabus at 17:06, 7 August 2017
2017-08-07T17:06:25Z
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Mabus
https://www.sciencemadness.org/smwiki/index.php?title=Potassium_sulfite&diff=5692&oldid=prev
Mabus: Created page with "{{Chembox | Name = Potassium sulfite | Reference = | IUPACName = Potassium sulfite | PIN = | SystematicName = | OtherNames = E225<br>Dipotassium sulfite<br>Potassium sulphite<..."
2016-10-30T14:48:48Z
<p>Created page with "{{Chembox | Name = Potassium sulfite | Reference = | IUPACName = Potassium sulfite | PIN = | SystematicName = | OtherNames = E225<br>Dipotassium sulfite<br>Potassium sulphite<..."</p>
<p><b>New page</b></p><div>{{Chembox<br />
| Name = Potassium sulfite<br />
| Reference =<br />
| IUPACName = Potassium sulfite<br />
| PIN =<br />
| SystematicName =<br />
| OtherNames = E225<br>Dipotassium sulfite<br>Potassium sulphite<br>Sulfurous acid, dipotassium salt<br />
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| AtmosphericOHRateConstant = <br />
| Appearance = White or slight yellowish solid<br />
| BoilingPt = <br />
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| BoilingPt_notes = Decomposes<br />
| Density = 2.35 g/cm<sup>3</sup> (20 °C)<ref>https://www.americanelements.com/potassium-sulfite-10117-38-1</ref><br />
| Formula = K<sub>2</sub>SO<sub>3</sub><br />
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| LogP = <br />
| MolarMass = 158.26 g/mol<br />
| MeltingPt = <br />
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| MeltingPt_notes = (decomposes)<br />
| pKa = 8<br />
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| Solubility = Soluble with hydrolysis<br />
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'''Potassium sulfite''' is a chemical compound with the formula '''K<sub>2</sub>SO<sub>3</sub>''', used as food preservative.<br />
<br />
==Properties==<br />
===Chemical===<br />
Potassium sulfite slowly oxidizes in air to [[potassium sulfate]]:<br />
<br />
:K<sub>2</sub>SO<sub>3</sub> + ½ O<sub>2</sub> → K<sub>2</sub>SO<sub>4</sub><br />
<br />
===Physical===<br />
Potassium sulfite is a white or slight yellowish solid, soluble in water but insoluble in organic solvents.<br />
<br />
==Availability==<br />
Potassium sulfite is sold by various suppliers in both solid form and as solution. It can sometimes be found on eBay.<br />
<br />
==Preparation==<br />
Potassium sulfite can be prepared by bubbling a predetermined volume of [[sulfur dioxide]] through an aqueous solution of [[potassium hydroxide]]. If an excess of sulfur dioxide is used, [[potassium bisulfite]] will form instead.<br />
<br />
:2 KOH + SO<sub>2</sub> → K<sub>2</sub>SO<sub>3</sub> + H<sub>2</sub>O<br />
<br />
Gentle evaporation is required to eliminate the water from the solution, as strong heating can hydrolyze the sulfite or oxidize it to sulfate. Alternatively, one can cool the resulting solution and obtain sulfite crystals.<br />
<br />
==Projects==<br />
*Reducing agent<br />
*Make (dry) sulfur dioxide generator<br />
*Make potassium sulfate<br />
*Make potassium bisulfite<br />
<br />
==Handling==<br />
===Safety===<br />
Potassium sulfite releases sulfur dioxide in contact with a strong acid, which is irritant and toxic.<br />
<br />
===Storage===<br />
As it slowly oxidizes in open air, potassium sulfite should be stored in air tight containers or in a sulfur dioxide atmosphere, at temperatures between 0-30 °C.<br />
<br />
===Disposal===<br />
Potassium bisulfite can be safely neutralized with bleach, hydrogen peroxide or simply left in open air to potassium sulfate which can be safely poured down the drain. However, it's not always necessary to neutralize it first.<br />
<br />
==References==<br />
<references/><br />
===Relevant Sciencemadness threads===<br />
*[http://www.sciencemadness.org/talk/viewthread.php?tid=23196 Clean Sulfur Dioxide Gas]<br />
<br />
[[Category:Chemical compounds]]<br />
[[Category:Inorganic compounds]]<br />
[[Category:Potassium compounds]]<br />
[[Category:Sulfites]]<br />
[[Category:Reducing agents]]<br />
[[Category:Materials unstable in acidic solution]]<br />
[[Category:Materials available as food grade]]</div>
Mabus