Nomenclature
CAS number: 16731-55-8
Potassium pyrosulfite.
K
2O
5S
2; mol wt 222.32.
K 35.17%, O 35.98%, S 28.85%.
K
2S
2O
5.
Description and references
The article of commerce contains ≈95% K2S2O5.
Properties
White crystals or cryst powder; sulfur dioxide
odor; acid reaction; liberates SO2 with acids; oxidizes
in air to sulfate, more readily in presence of moisture. It may catch
fire if much heat develops in powdering it. Freely sol in water;
insol in alcohol. Keep dry and well closed.Use
As antifermentative in breweries and wineries; bleaching
straw; preservative for fruits and vegetables.