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Chemistry · PYQ NEET UG 2017
हिन्दीA first order reaction has a specific reaction rate of \( 10^{-2} \text{ sec}^{-1} \). How much time will it take for 20 g of the reactant to reduce to 5 g?
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Correct answer · Option A
138.6 s
Explanation
For a first order reaction, \( t = \frac{2.303}{k} \log(\frac{[A]_0}{[A]}) = \frac{2.303}{10^{-2}} \log(\frac{20}{5}) = 230.3 \times \log(4) = 230.3 \times 0.6021 \approx 138.6 \text{ s} \).
