Question

If the solubility product of lead iodide is 3.2 × 10⁻⁸, its solubility will be ____________.

Options

• 2 × 10⁻³ M

• 4 × 10⁻⁴ M

• 1.6 × 10⁻⁵ M

• 1.8 × 10⁻⁵ M

Answer 1

If the solubility product of lead iodide is 3.2 × 10⁻⁸, its solubility will be 2 × 10⁻³ M.

Explanation:

\[\ce{PbI2_{(s)} ⇌ Pb^{2+}_{( aq)} + 2I^-_{( aq)}}\]

K_sp = (s) (2s)²

3.2 × 10⁻⁸ = 4s³

s = `((3.2 xx 10^-8)/4)^(1/3)`

= `(8 xx 10^-9)^(1/3)`

= 2 × 10⁻³ M