Product Name: Sodium metabisulfite CAS: 7681-57-4 MW:190.11 MF:2Na.O5S2 Appearance:White crystalline powder Purity:98% Specification Items Standard Sodium metabisulfite % 98%min Water insoluble % 0.01max Fe % 0.002max As % 0.00006max Heavy Metals(Pb) % 0.0003max PH value 4.0-4.6 Application 1. Used as chromatographic analysis reagent, preservative and reducing agent for dyes 2. Used as bleaching agent, mordant, reducing agent, rubber coagulant 3. Printing and dyeing industry used as dechlorination agent after cotton bleaching, cotton cooking additives. Product packaging