MHT CET202313 May 2023Morning ShiftChemistryChemical KineticsActual
Calculate the rate constant of the first order reaction if 20 % of the reactant decomposes in 15 minutes.
Options
- A1.488 10⁻² minute ⁻¹
- B1.881 10⁻² minute ⁻¹
- C1.984 10⁻² minute ⁻¹
- D1.18 10⁻² minute ⁻¹
Correct answer
A. 1.488 10⁻² minute ⁻¹
Step-by-step solution
20 % of the reactant has decomposed. So, if [A]₀=100 , then [A]_ t =100-20=80 aligned k & = 2.303 t ₁₀ [ A ]₀ [ ~A ]_ t & = 2.303 15 ₁₀ 100 80 & = 2.303 15 ₁₀ 5 4 & = 2.303 15 ( ₁₀ 5- ₁₀ 4 ) & = 2.303 15 (0.699-0.602) & =0.01488=1.488 10⁻² minute ⁻¹ aligned