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JEE Main202226 Jul 2022Evening ShiftChemistryChemical KineticsActual

At 30 ° C , the half life for the decomposition of AB 2 is 200 s and is independent of the initial concentration of AB 2 . The time required for 80 % of the AB 2 to decompose is (Given: log 2 = 0 . 30 ; log 3 = 0 . 48 )

Options

  1. A200 s
  2. B323 s
  3. C467 s
  4. D532 s

Correct answer

C. 467 s

Step-by-step solution

Since half life is independent of intial concentration of the reactant, it's a first order reaction k = ln   2 t 1 2 kt = 2 . 303   log A 0 A ln   2 t 1 2 t = 2 . 303   log A 0 A 2 . 303   log   2 200 t = 2 . 303   log 100 20 t = 200 0 . 3 × log   5 = 466 . 67   sec ≈ 467   sec

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