Serial No. Metal Salt used Mol wt. Atomic wt. Weight of 10ml stock solution (mg) 1 Chromium K2Cr2O7 294 52 170 2 Cadmium CdCl2 183 112 49 3 Cobalt CoCl2 130 59 66 4 Copper CuSO4 160 64 75 5 Lead PbCl2 278 207 40 6 Nickel NiCl2 130 57 68

Table 1: Preparation of stock solution of heavy metal compounds.