Q36 / 150 · MHT CET 2024 (03 May Shift 2) · Chemistry
Calculate ' $\alpha$ ' for 0.1 M acetic acid $\left(\mathrm{K}_{\mathrm{a}}=1.0 \times 10^{-5}\right)$
- Correct answerA$10^{-2}$
- B$10^{-3}$
- C$10^{-4}$
- D$10^{-5}$
Solution
For a weak acid HA, $\alpha$ is very small, or
$\begin{aligned}
& (1-\alpha) \cong 1 \\
& \therefore \quad \alpha=\sqrt{\frac{\mathrm{K}_{\mathrm{a}}}{\mathrm{c}}}=\sqrt{\frac{1.0 \times 10^{-5}}{0.1}}=10^{-2}
\end{aligned}$
Hence, the correct answer is option: 'A'.