114. Solving a chemistry problem

114. Solving a chemistry problem

To determine lead in the ore, a 5.000 g sample of the ore was taken. After dissolving it in acid, the Pb2 ion was precipitated in the form of PbCrO4, the precipitate was filtered, washed, and dissolved in a mixture of HCl and KI (reaction equation?). The iodine released during this reaction was titrated with 0.5000 N. Na2S2O3 solution and consumed 42.00 cm3. What percentage of lead does the ore contain?

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