Chemical Specifications Appearance White Crystals, Crystalline Powder and/or Chunks Assay (acidimetric) 97.0 - 102.0% pH (1% solution) 7.6 - 8.2 Chloride (Cl) Max 0.002% Sulphate (SO4) Max 0.02% Heavy metal (as Pb) Max 0.001% Arsenic (As) Max 0.0003%