Name of indexIndexActual index Na2H2P2O7 % ≥95.0 96.2 Substances not dissolved in water % ≤1.0 0.02 PH value 3.5-4.5 4.1 Heavy metal (Pb) % ≤0.0015<0.001 Fluorides (F) % ≤0.005<0.001 As % ≤0.0003<0.0003 Appearance White Powder Measure upResult : First Grade