Question

A solution is 0.025 m in pb2+. what minimum concentration of cl− is required to begin to precipitate pbcl2. the ksp for pbcl2 is 1.17 × 10−5.

Answer 1

Answer is:  minimum concentration of chlorine anion is 0.0216 M.
Balanced chemical reaction: Pb²⁺(aq) + 2Cl⁻(aq) → PbCl₂(s).
[Pb²⁺] = 0.025 M.
Ksp = 1.17·10⁻⁵.
Ksp = [Pb²⁺] · [Cl⁻]².
[Cl⁻] = √Ksp ÷ [Pb²⁺].
[Cl⁻] = √0.0000117 ÷ 0.025.
[Cl⁻] = 2.16·10⁻² M.