66. Solving a chemistry problem

10. During amperometric titration of 50.0 ml of a solution containing barium and lead ions with a 0.050 M solution of potassium chromate at a potential of -0.80 V, the following results were obtained:
V(K2CrO4), ml 0 1.0 2.0 3.0 4.0 6.0 8.0 10.0 11.0 12.0 13.0
I, μA 90 70 50 30 10 10 10 10 35 65 80
Construct an amperometric titration curve and calculate the content of lead and barium (mg/ml) in the analyzed solution. Which of the substances participating in the reaction (determined, titrant, products) are electroactive in this case.