47. Solving a chemistry problem

1. When determining lead, an organic reagent was used that forms a colored complex with a composition of 1:1 with lead ions. The concentrate from the aqueous extract of the analyzed sample contains 2.07×10-3 g/l Pb2 and an excess of the reagent. The optical density of the concentrate is 0.63 (λ=440 nm, l=1.0 cm). Calculate the molar light absorption coefficient.