Introduction: appearance: white crystals clarity and colour of solution: passes test. purity: 99.0-101.0% water: 11-13% heavy metals: 10ppm max. oxalate: 300ppm max. chloride: 50ppm max. sulphate: 150ppm max. readily carbonsable substances: passes test alkalinity: passes test solubility: passes test results: complies with the specification of BP98.