A solution contains 1.0 × 10–2 M Pb2+. Drops of a 5.0 × 10–1 M solution of NaBr were added through a microburet?

The solubility equilibrium for the dissolving of PbBr₂ :
PbBr₂(s) ⇌ Pb²⁺(aq) + 2Br⁻(aq) …… Ksp = 4.67 × 10⁻⁶

Neglect the slight change in volume resulting from the added NaBr solution.
[Pb²⁺] = 5.0 × 10⁻¹ M
[Br⁻] = 3.0 × 10⁻² M

Reaction quotient, Q = [Pb²⁺] [Br⁻]² = (5.0 × 10⁻¹) × (3.0 × 10⁻²)² = 4.5 × 10⁻⁴ > Ksp
Hence, precipitation occurs.

The answer : B : Yes, a precipitate will form.

B :
Yes, a precipitate will form

Q > Ksp

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