Caustic soda Purity quotient: 99%, 96% Casr: 1310-73-2 Appearance flakes/pearls Naoh % min 99.0 Na2co3 % max 0.5 Nacl % max 0.05 Fe2o3 % max 0.006 Molecular weight: 40.01 Casrn :1310-73-2 Density: 2.130 g/cm3 Water solubility: very soluble colorless solution Base dissociation constant (kb) = 3.0 Base dissociation constants of the countdown to the number (pkb) =- 0.48 25kg/bag