Chemical Specifications Appearance White granules or powder; odourless or· with slight put not unpleasant odour. The pentahydrate is somewhat efflorescent. Assay (as C6H10Ca06; on dried basis) 98.0-102.0% Identification Passes IP test Acidity or alkalinity Passes IP test Arsenic (As) Max 0.0002% Heavy metal (as Pb) Max 0.002% Iron (Fe) Max 0.008% Chlorides Max 0.02% Sulphates Max 0.15% Reducing substance Passes IP test Loss on drying (at 120°C; 4 hrs) Max 30.0%