56. Solution to Chemistry Problem

20. Determine the concentration (mg/l) of nickel in the test solution if the following results were obtained during amperometric titration of 20.00 ml of this solution with an alcoholic solution of dimethylglyoxime (DMGO) with T(DMGO/Ni)=0.00203:
V(DMGO), ml Diffusion current Id, μA, for variants
1 2 3 4 5
0.0 240 160 220 260 279
0.5 190 115 100 225 250
1.0 93 46 40 158 186
2.0 41 65 62 124 153
2.5 76 85 85 100 122
3.0 110 104 106 148 90
3.5 145 122 127 192 80
4.0 180 140 148 240 100