Practice question
Question
The Ksp of PbSO₄ is 1.6 × 10⁻⁸ . In a 0.01 M Na₂SO₄ solution, what is [Pb²⁺] in a saturated solution?
Explanation
For PbSO₄ <=> Pb²⁺ + SO₄²⁻ , Ksp = [Pb²⁺][SO₄²⁻] = 1.6 × 10⁻⁸ . [SO₄²⁻] = 0.01 + [Pb²⁺ ≈ 0.01 M (since [Pb²⁺ is small). [Pb²⁺] = (1.6 × 10⁻⁸/0.01) = 1.6 × 10⁻⁶ M .