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MHT CET · Chemistry · Chemical Kinetics

Calculate the time required for reactant to decrease the concentration from \(100 \%\) to \(20 \%\), if rate constant of first order reaction is 0.02303 hours \(^{-1}\).

  1. A 28 hour
  2. B 42 hour
  3. C 56 hour
  4. D 70 hour
Verified Solution

Answer & Solution

Correct Answer

(D) 70 hour

Step-by-step Solution

Detailed explanation

\(\begin{aligned} & \mathrm{kt}=\ln \frac{\left[\mathrm{A}_0\right]}{\mathrm{A}} \\ & 0.02303 \text { hour }^{-1} \times \mathrm{t}=\ln \frac{100}{20} \\ & \mathrm{t}=69.88 \text { hour } \approx 70 \text { hour }\end{aligned}\)