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Chemistry · PYQ NEET UG 2016(1)
हिन्दीThe rate of a first-order reaction is \( 0.04 \text{ mol L}^{-1}\text{s}^{-1} \) at 10 seconds and \( 0.03 \text{ mol L}^{-1}\text{s}^{-1} \) at 20 seconds after initiation of the reaction. The half-life period of the reaction is ______.
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Correct answer · Option B
\( 24.1 \text{ s} \)
Explanation
For a first-order reaction, \( k = \frac{2.303}{t_2 - t_1} \log \frac{r_1}{r_2} = \frac{2.303}{10} \log \frac{0.04}{0.03} = 0.02877 \text{ s}^{-1} \). Then \( t_{1/2} = \frac{0.693}{k} = \frac{0.693}{0.02877} \approx 24.1 \text{ s} \).
