52. Solution to Chemistry Problem

16. To determine lead in zinc ore by the addition method, a sample of ore weighing m g was dissolved in a mixture of acids, iron (III) was reduced, gelatin was added, and the solution was diluted to 200.0 ml. An aliquot of 20.00 ml was placed in an electrolyzer and the height h1 of the polarographic wave was measured at E = -0.45 V (NCE). Under these conditions, copper, zinc, and cadmium ions do not interfere with the determination of lead. After adding a standard solution of VCT ml 0.0020 M Pb(NO3)2 to the electrolyzer, the wave height h2 was obtained.
Calculate the mass fraction (%) of lead in the ore for the following options:
Option 1
m, g 1.000
h1, mm 22.0
Vst, ml 10.00
h2, mm 42.0