Chemistry Reaction Kinetics BUMHS 2022
PMDC Verified Question 38 of 80
What a catalyst work by?
A
Increasing the frequency of collisions
B
Increasing the proportion of particles with energy greater than the activation energy
C
Increasing the activation energy.
D
Increasing the concentration
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Increasing the proportion of particles with energy greater than the activation energy
Concept:

A catalyst speeds up a chemical reaction by providing an alternative pathway with a lower activation energy barrier.

Solution:

  • Because the new activation energy (\( E_a \)) is lower, the threshold energy required for a successful collision drops.
  • Consequently, a much larger proportion (or fraction) of the reactant molecules at the given temperature now possess enough kinetic energy to cross this lowered barrier.
  • This exponential increase in successful collisions drastically increases the reaction rate.


Why other options are incorrect:

Catalysts do not change the concentration or the fundamental frequency of collisions (which is driven by temperature). A catalyst decreases, not increases, the activation energy.

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