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MHT CET202525 Apr 2025Evening ShiftChemistryChemical KineticsActual

What is the time required for 99 % completion of a first order reaction if rate constant is 23.03 ~min ⁻¹ ?

Options

  1. A0.2 minute
  2. B0.4 minute
  3. C6.2 minute
  4. D8.1 minute

Correct answer

A. 0.2 minute

Step-by-step solution

For a first-order reaction with 99 % completion, the remaining concentration is [ R ]_t = 0.01[ R ]₀ , giving the ratio [ R ]₀ [ R ]_t = 100 . Given k = 23.03~ min ⁻¹ , the integrated rate law t = 2.303 k [ R ]₀ [ R ]_t yields: t = 2.303 23.03 100 = 0.1 2 = 0.2~ min This corresponds to option A .

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