Potassium bisulfite

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Not to be confused with potassium metabisulfite.
Potassium bisulfite
Names
IUPAC name
Potassium hydrogen sulfite
Other names
E228
Monopotassium sulfite
Potassium bisulphite
Sulfurous acid, monopotassium salt
Properties
KHSO3
Molar mass 120.1561 g/mol
Appearance White crystalline powder
Odor Sulfur dioxide
Melting point 190 °C (374 °F; 463 K) (decomposes)
Boiling point Decomposes
49 g/100 mL (20 °C)
115 g/100 mL (100 °C)
Solubility Insoluble in alcohols, benzene, toluene
Hazards
Safety data sheet CAMEO (solution)
Flash point Non-flammable
Related compounds
Related compounds
Potassium sulfite
Potassium bisulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Potassium bisulfite or potassium hydrogen sulfite is a chemical compound with the chemical formula KHSO3. The compound is commonly used in food industry, for sterilizing wine, as food additive E228. While it can be found as solid, it is more commonly encountered as solution.

Properties

Chemical

Potassium bisulfite oxidizes in air to potassium bisulfate.

Addition of a base raises the pH, converting the compound in potassium sulfite.

Physical

Potassium bisulfite is a white solid, with a sulfurous smell, soluble in water.

Availability

Potassium bisulfite is sold as both solid and solution, with the latter being more available. Make sure to check the product label/designation, as some products labeled as potassium bisulfite are actually potassium metabisulfite.

It is available as the food additive E228.

Preparation

Can be prepared by bubbling and excess of sulfur dioxide through a solution of potassium carbonate or potassium hydroxide.

Projects

  • Reducing agent
  • Make potassium bisulfate

Handling

Safety

Potassium bisulfite releases toxic sulfur dioxide gas. Work in a well ventilated area or fumehood.

Storage

Should be stored in closed, air-tight bottles.

Disposal

Can be neutralized with bleach or hydrogen peroxide, then with a base to potassium sulfate.

References

Relevant Sciencemadness threads