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Which of the following statements correctly describes the effect of a catalyst on the activation energy () of a reaction?

medium MCQ 2 marks Class 12 · Chemistry · Chemical Kinetics
  1. A catalyst increases the activation energy of the reaction.
  2. A catalyst provides an alternative pathway with a lower activation energy.
  3. A catalyst changes the overall free‑energy change ( G) of the reaction.
  4. A catalyst is consumed and does not reappear after the reaction.
Answer
A catalyst provides an alternative pathway with a lower activation energy.

The correct answer is A catalyst provides an alternative pathway with a lower activation energy. — Hence the correct choice is option (B).

Step-by-step solution

  1. Read each option carefully and recall the definition of a catalyst: it speeds up a reaction by lowering without being consumed.
  2. Option (A) states that a catalyst increases the activation energy – this contradicts the definition, so it is false.
  3. Option (B) states that a catalyst provides an alternative pathway with a lower activation energy – this matches the textbook definition, so it is correct.
  4. Option (C) claims that a catalyst changes the overall free‑energy change () of the reaction – a catalyst does not affect thermodynamics, only kinetics, so false.
  5. Option (D) suggests that a catalyst is consumed in the reaction – catalysts are regenerated, so false.
  6. Hence the correct choice is option (B).
Common mistake: Thinking that a catalyst changes the equilibrium position or is consumed during the reaction.

Concept tested: Catalyst effect on activation energy

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