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MHT CET202620 April 2026Morning ShiftChemistryChemical KineticsActual

Calculate rate constant of a first order reaction having half life 1 minute 40 second?

Options

  1. A1.76 10⁻³ s ⁻¹
  2. B2.31 10⁻³ s ⁻¹
  3. C6.93 10⁻³ s ⁻¹
  4. D4.61 10⁻³ s ⁻¹

Correct answer

C. 6.93 10⁻³ s ⁻¹

Step-by-step solution

Given half-life of the first order reaction, t_ 1/2 = 1 minute 40 seconds Converting to seconds, t_ 1/2 = 60 + 40 = 100 s For a first order reaction, the rate constant k is given by the relation: k = 0.693 t_ 1/2 Substituting the value of t_ 1/2 : k = 0.693 100 s k = 6.93 10⁻³ s ⁻¹ Answer: 6.93 10⁻³ s ⁻¹

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