MHT CET20239 May 2023Evening ShiftChemistryChemical KineticsActual
Calculate the rate constant of first order reaction if the concentration of the reactant decreases by 90 % in 30 minutes.
Options
- A7.7 10⁻² minute ⁻¹
- B4.2 10⁻² minute ⁻¹
- C2.1 10⁻² minute ⁻¹
- D3.5 10⁻² minute ⁻¹
Correct answer
A. 7.7 10⁻² minute ⁻¹
Step-by-step solution
Concentration decreases by 90 % . Hence, 10 % reactant is left after 30 minutes. aligned k & = 2.303 t ₁₀ [ A ]₀ [ ~A ]_ t k & = 2.303 30 ₁₀ 100 10 & = 2.303 30 ~min & =7.7 10⁻² ~min ⁻¹ aligned