MHT CET202415 May 2024Morning ShiftChemistryChemical KineticsActual
A first order reaction takes 40 minute for 20 % decomposition. Calculate its rate constant.
Options
- A5.6 10⁻³ minute ⁻¹
- B4.5 10⁻³ minute ⁻¹
- C6.5 10⁻³ minute ⁻¹
- D7.2 10⁻³ minute ⁻¹
Correct answer
A. 5.6 10⁻³ minute ⁻¹
Step-by-step solution
If [A]₀=100 , then [A]_t=100-20=80 For a first order reaction, aligned k & = 2.303 t ₁₀ [ ~A ]₀ [ ~A ]_ t = 2.303 40 ~min ₁₀ 100 80 & = 2.303 40 ~min ₁₀ 1.25= 2.303 40 ~min 0.097 & =5.57 10⁻³ minute ⁻¹ 5.6 10⁻³ minute ⁻¹ aligned