According to GB1893-2008 Commodity Name:sodium metabisulfite(Food additive) or sodium pyrosulfite Molecular Formular:Na2S2O5 Molecular Weight:190 ... . It is slightly soluable in alcohols.Usage:Sodium metabisulfite is widely used in leather tanning, cloth ... knitting, organic matters blanching, mordants, food preservation, brewing, sterilization and antisepsis of beverage, synthetic ...