Appearance Clear colorless liquid Assay (alkalimetric) Min 99.5% Weight/ mL at 20°C 1.047 - 1.052 g Freezing point 15.5 deg C Chloride (Cl) Max 0.0005% Sulphate (SO4) Max 0.0005% Arsenic (As) Max 0.0002% Iron (Fe) Max 0.0002% Lead (Pb) Max 0.0002% Non volatile matter Max 0.01%