Question

The ionic strength of a solution containing 0.01M of $CaCl_2$ and 0.001M of $Na_2SO_4$ is _____ M (rounded off to 3 decimal places)

Answer 1

Correct Answer: 0.033

Step 1: Calculate the contribution of ions from \( \text{CaCl}_2 \). \[ I_{\text{CaCl}_2} = \frac{1}{2} \left( 0.01 \times 4 + 0.02 \times 1 \right) = 0.03 \, \text{M} \] Step 2: Calculate the contribution of ions from \( \text{Na}_2\text{SO}_4 \). \[ I_{\text{Na}_2\text{SO}_4} = \frac{1}{2} \left( 0.002 \times 1 + 0.001 \times 4 \right) = 0.003 \, \text{M} \] Step 3: Sum the contributions to find total ionic strength. \[ I = 0.03 + 0.003 = 0.033 \, \text{M} \]