Question

The solubility product of Agl is 1.56 x 10⁻¹⁶. What iodide ion concentration will be required to precipitate Agl from 0.01 M AgNO³ solution?

Answer 1

\[\ce{Agl(s) <=> \underset{s}{\underset{saturated}{Ag+(aq)}} + \underset{s}{\underset{solution}{I-(aq)}}}\]

k_sp = [Ag⁺][I⁻ ]

1.56 × 10⁻¹⁶ = 0.01 [I⁻]  ∴ [I⁻] = 1.56 × 10⁻¹⁴ mol dm⁻³

When [I⁻] = 1.56 × 10⁻¹⁴ mol dm⁻³, the solution will be saturated.

When [I⁻] exceeds this value, AgI gets precipitated.

∴ for precipitation of Agl, [I⁻] > 1.56 × 10⁻¹⁴ mol dm⁻³