TO determine the minimum concentration that is required, we write the solubility constant expression from the dissociation reaction of the compound. It would be as follows:
PbCl2 = Pb2+ + 2Cl-
Ksp = [Pb2+] (2[Cl-])^2
1.17×10−5 = (x)(4x^2) = 4x^3
x = 0.0143 M
Therefore, the minimum concentration of Cl- would be 2(0.0143) = 0.0286 M.
