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WBJEE · Chemistry · Chemical Kinetics

The time taken for \(10 \%\) completion of a first order reactin is 20 mins. Then, for \(19 \%\) completion, the reaction will take

  1. A \(40 \mathrm{mins}\)
  2. B 60 mins
  3. C \(30 \mathrm{mins}\)
  4. D 50 mins
Verified Solution

Answer & Solution

Correct Answer

(A) \(40 \mathrm{mins}\)

Step-by-step Solution

Detailed explanation

\(t=\frac{2.303}{\lambda} \log \frac{\mathrm{N}_0}{\mathrm{~N}}\) \(\begin{aligned} & 20=\frac{2.303}{\lambda} \log \frac{100}{90} \\ & t=\frac{2.303}{\lambda} \log \frac{100}{81}\end{aligned}\) equation (i) / (ii) \(\therefore t=40 \mathrm{~min}\).