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MHT CET Chemistry Chemical Kinetics 2026 MHT CET 2026 (11 April Shift 2)

MHT CET Chemistry Question (2026) — Solution

Question

Half life period of a first order reaction is 1386 seconds. The rate constant of the reaction is

Options

  1. A. 5.5 10^ -2 s^ -1
  2. B. 0.5 10^ -3 s^ -1
  3. C. 5 10^ -2 s^ -1
  4. D. 5 10^ -3 s^ -1

Answer

B. 0.5 10^ -3 s^ -1

Step-by-step solution

For a first order reaction, the rate constant k is related to the half life period t_ 1/2 by the formula: k = 0.693 t_ 1/2 Given t_ 1/2 = 1386 s , substituting this value: k = 0.693 1386 k = 693 10^ -3 2 693 k = 0.5 10^ -3 s ^ -1 Answer: 0.5 10^ -3 s^ -1

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