52. Solving a chemistry problem

2. During amperometric titration of a lead solution with a working solution of potassium sulfate with a volume of 10.0 cm³, a molar concentration of 0.1235 mol / dm³, with a potential of E = 1.0 V, the following parameters are given:
Titrant volume, cm³: 0 0.5 1.0 1.5 2.0 2.5
Current strength, µA: 308 240 172 102 42 42
Determine the mass fraction of lead in the test solution.