Q124 / 200 · MHT CET - Medical 2026 (24 April Shift 1) · Chemistry
A 0.02 M KCl solution has conductivity $k=2.76\times10^{-3}\ \text{S cm}^{-1}$. Find molar conductivity.
- A$130\ \text{S cm}^2\text{mol}^{-1}$
- Correct answerB$138\ \text{S cm}^2\text{mol}^{-1}$
- C$148\ \text{S cm}^2\text{mol}^{-1}$
- D$150\ \text{S cm}^2\text{mol}^{-1}$
Solution
Molar conductivity $\Lambda_m$ is given by the formula:
$\Lambda_m = \dfrac{k \times 1000}{M}$
Given:
$k = 2.76 \times 10^{-3}\ \text{S cm}^{-1}$
$M = 0.02\ \text{M}$
Substituting the values:
$\Lambda_m = \dfrac{2.76 \times 10^{-3} \times 1000}{0.02}$
$\Lambda_m = \dfrac{2.76}{0.02}$
$\Lambda_m = 138\ \text{S cm}^2\text{mol}^{-1}$
Answer: $138\ \text{S cm}^2\text{mol}^{-1}$
$\Lambda_m = \dfrac{k \times 1000}{M}$
Given:
$k = 2.76 \times 10^{-3}\ \text{S cm}^{-1}$
$M = 0.02\ \text{M}$
Substituting the values:
$\Lambda_m = \dfrac{2.76 \times 10^{-3} \times 1000}{0.02}$
$\Lambda_m = \dfrac{2.76}{0.02}$
$\Lambda_m = 138\ \text{S cm}^2\text{mol}^{-1}$
Answer: $138\ \text{S cm}^2\text{mol}^{-1}$
Hence, the correct answer is option: 'B'.