Question

Solubility of binary sparingly soluble salt is \(1.12 \times 10^{-4} \mathrm{~g} / \mathrm{dm}^3\). Calculate its solubility product (molar mass of salt \(=112 \mathrm{~g} \mathrm{~mol}^{-1}\) )

• A. \(1\times 10^{-3}\)
• B. \(1\times 10^{-6}\)
• C. \(1\times 10^{-9}\)
• D. \(1\times 10^{-12}\)

Hint:

Convert the solubility to mol per dm cubed, then square it for a binary salt.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
For a binary salt \(\text{AB} \rightleftharpoons \text{A}^{+} + \text{B}^{-}\), \(K_{sp} = S^2\).

Step 2: Molar Solubility
\(S = \dfrac{1.12\times 10^{-4}\ \text{g dm}^{-3}}{112\ \text{g mol}^{-1}} = 1\times 10^{-6}\ \text{mol dm}^{-3}\)

Step 3: Calculation
\(K_{sp} = (1\times 10^{-6})^2 = 1\times 10^{-12}\)

Final Answer:
The solubility product is \(1\times 10^{-12}\). \[ \boxed{\text{(D) }1\times 10^{-12}} \]