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MHT CET202016 Oct 2020Morning ShiftChemistryChemical KineticsActual

A first order reaction has rate constant 1 10⁻² ~s ⁻¹ . What time will it take for 20 ~g of reactant to reduce to 5 ~g ?

Options

  1. A346.5 ~S
  2. B238.6 ~S
  3. C138.6 ~S
  4. D693.0 ~S

Correct answer

C. 138.6 ~S

Step-by-step solution

(A) k =1 10⁻² ~s ⁻¹, [ ~A ]₀=20 ~g ,[ ~A ]_ t =5 ~g For first order reaction, t= 2.303 k ₁₀ [A]₀ [A]_ t t= 2.303 1 10⁻² ₁₀ 20 5 t =2.303 0.602 10²=138.6 ~s

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