7. To determine lead in zinc ore using the additive method, a sample of ore weighing (m-g) was dissolved in a mixture of acids, iron (3) was reduced, gelatin was added and the solution was diluted to 200 ml. An aliquot with a volume of 20 ml was placed in an electrolyzer and the height (h1) of the polarographic wave was measured at E = -0.45 V (NKE). Under these conditions, copper, zinc, and cadmium ions do not interfere with the determination of lead. After adding a standard solution (V-ml) of 0.0020 M Pb(NO3)2. We obtained the wave height (h2)Calculate the mass fraction of lead in the ore for the following:
Option
1:mg=1.000;h1(mm)=22;Vst=10ml;h2=42

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