Chapter 18, Problem 22E

What $\left[{\text{l}}^{\text{-}}\right]$ should be maintained in Kl(aq) to produce a solubility of $\text{1}\text{.5}\times {\text{10}}^{-3}$ mol ${\text{Pbl}}_{\text{2}}$ when ${\text{Pbl}}_2$ is added?