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Chemistry · PYQ NEET UG 2025
हिन्दीIf the rate constant of a reaction is \( 0.03 \text{ s}^{-1} \), how much time does it take for \( 7.2 \text{ mol L}^{-1} \) concentration of the reactant to get reduced to \( 0.9 \text{ mol L}^{-1} \)? (Given: \( \log 2 = 0.301 \))
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Correct answer · Option A
69.3 s
Explanation
For a first order reaction, \( t = \frac{2.303}{k} \log(\frac{[A]_0}{[A]}) = \frac{2.303}{0.03} \log(\frac{7.2}{0.9}) = \frac{2.303 \times 3 \log 2}{0.03} \approx 69.3 \text{ s} \).
