Difference between revisions of "Potassium bicarbonate"

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==Projects==
 
==Projects==
 +
*Make potassium carbonate
 
*Make potassium salts
 
*Make potassium salts
 
*Buffering agent
 
*Buffering agent

Latest revision as of 20:49, 15 January 2019

Potassium bicarbonate
Potassium bicarbonate sample bottle.jpg
Potassium bicarbonate, slightly wet, on a watch glass.
Names
IUPAC name
Potassium hydrogen carbonate
Other names
Potassium acid carbonate
Properties
KHCO3
Molar mass 100.115 g/mol
Appearance White hygroscopic salt
Odor Odorless
Density 2.17 g/cm3
Melting point 292 °C (558 °F; 565 K) (decomposes)
Boiling point Decomposes
33.7 g/100 mL (20 °C)
60 g/100 mL (60 °C)
Solubility Reacts with acids
Insoluble in alcohols, benzene, chloroform, toluene
Vapor pressure ~0 mmHg
Acidity (pKa) 10.329
Thermochemistry
-963.2 kJ/mol
Hazards
Safety data sheet AcrosOrganics
Flash point Non-Flammable
Lethal dose or concentration (LD, LC):
> 2000 mg/kg (rat, oral)
Related compounds
Related compounds
Potassium carbonate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Potassium bicarbonate or potassium hydrogen carbonate is a hygroscopic colorless salt of potassium with the formula KHCO3.It is used as a food additive in the European Union, E 501. It can be found in nature as the rare mineral kalicinite.

Properties

Chemical

Potassium bicarbonate decomposes to potassium carbonate if heated above 290 °C, despite some sources claiming the decomposition occurring at 100 or 120 degrees C.

2 KHCO3 → K2CO3 + CO2 + H2O

Potassium bicarbonate, like its sodium counterpart will react with acids to form potassium salt of the said acid.

KHCO3 + HCl → KCl + H2O + CO2

Physical

Potassium bicarbonate is a white hygroscopic solid, soluble in water but insoluble in alcohols and other organic solvents.

Availability

Potassium bicarbonate is sold by winemaking stores as a pH regulator/buffer. It is more expensive than sodium bicarbonate.

Some low-sodium baking powders may contain potassium bicarbonate, though most have calcium or magnesium carbonate, so always read the label.

Preparation

Potassium bicarbonate can be made by bubbling carbon dioxide into a solution containing potassium carbonate.

If you have a mixture of potassium and sodium hydroxide, you can dissolve it in alcohol and then bubble excess carbon dioxide in the solution. As potassium bicarbonate is insoluble in alcohol, it will precipitate, while sodium bicarbonate will stay in solution.

Projects

  • Make potassium carbonate
  • Make potassium salts
  • Buffering agent
  • Fungicide

Handling

Safety

Potassium bicarbonate is considered safe and doesn't require special handling.

Storage

Potassium bicarbonate should be kept in closed bottles. Since it's hygroscopic, it's best to keep it in a desiccator.

Disposal

No special disposal is required. Discard it as you wish.

References

Relevant Sciencemadness threads