anhydrous sodium sulfite sodium sulfite Application: medicine, papermaking, tannage, leather, printing, dyeing, bleachin sodium sulfiteMolecular Formula: Na2SO3Molecular Weight: 126.04Purity:96%CAS No.: 7757- ... long time. Index NamePremium gradeSodium sulfite ( Na2SO3 ) , % ≥96%Fe , ?≤0.005Water insoluble matter , % ≤0.03Free alkali ( as Na2SO3 ) , % ≤0.4 96% Anhydrous Sodium Sulfite