Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
COMEDK202510 May 2025Morning ShiftChemistryChemical KineticsActual

Two chemical reactions of the same order have equal Frequency factor value. Their Activation energies differ by 26.8 ~kJ / mol . At 300 K if k₂=x k₁ find the value of x .

Options

  1. A1.143 10^3
  2. B4.665
  3. C4.639 10^4
  4. D2.286 10^3

Correct answer

C. 4.639 10^4

Step-by-step solution

The Arrhenius equation is given by k = A e^ -E_a / (RT) . Given that the frequency factors are equal, A₁ = A₂ = A . The rate constants for the two reactions are k₁ = A e^ -E_ a1 / (RT) and k₂ = A e^ -E_ a2 / (RT) . Taking the ratio k₂ / k₁ = e^ (E_ a1 - E_ a2 ) / (RT) . Given E_ a1 - E_ a2 = 26.8 kJ/mol = 26800 J/mol , T = 300 K , and R = 8.314 J K ⁻¹ mol ⁻¹ . Substituting the values: x = k₂ / k₁ = e^ 26800 / (8.314 300) . x = e^ 26800 / 2494.2 = e^ 10.7449 . x 46397 . Answer: 4.639 10^4

Practice Chemical Kinetics on Quantrex Academy →

More from Chemical Kinetics

When the concentration of the reactant in a given reaction is halved and if the rate of reaction is halved, the order of the reaction is: 2026A first order reaction is 50%complete in 30 minutes at 300 K and in 10 minutes at 320 K. The activation energy of the reaction (E_a ) is: [R=8.314 J K ⁻¹ mol ⁻¹ ; log 2 = 0.3010; l 2026In the synthesis of NH₃ from H₂ and N₂ , if 6 10⁻² mole of hydrogen disappears in 10 minutes, the number of moles of NH₃ formed in 0.3 minutes is: 2026The initial pressure of the system before decomposition for a first order gas phase reaction A_ (g) B_ (g) + C_ (g) was P_i . After lapse of time 't', total pressure of the system 2026Which of the following factors is altered by the addition of a catalyst during a chemical reaction? 2026The rate constants for two different reactions, k₁ and k₂ are 10¹⁶ e^ -2000/T and 10¹⁵ e^ -1000/T respectively. The temperature at which k₁ = k₂ is 202660% of a first order reaction was completed in 60 min, then 50% of the same reaction can be completed in: [log 4 = 0.60, log 5=0.69] 2026Identify the correct values to be plotted in the graph, the slope of which can be used to determine the activation energy of a reaction. 2026 Full Chemical Kinetics list All COMEDK PYQs