Answer:
The correct answer is 5.6 × 10⁻²³ M.
Explanation:
As a highly soluble salt, KBr dissolves easily in water, while Hg₂Br₂ is very less soluble in comparison to KBr.
Let the solubility of Hg₂Br₂ is S mol per liter.
Therefore,
KBr (s) (1.0 M) ⇒ K⁺ (aq) (1M) + Br⁻ (aq) (1M)
Hg₂Br₂ (s) (1-S) ⇔ Hg₂⁺ (aq) (S) + 2Br⁻ (aq) (2S)
Net [Br-] = (2S + 1) M
Ksp = S (2S + 1)²
Ksp = S (4S² + 1 + 4S)
Ksp = 4S³ + S + 4S²
As the solubility is extremely less, therefore, we can ignore S² and S³. Now,
Ksp = S = 5.6 × 10⁻²³ M
Hence, the solubility of Hg₂Br₂ is 5.6 × 10⁻²³ M.
