Which of the following statements is incorrect with respect to the use of a catalyst in the reversible reaction?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → The catalyst increases the rate of only the forward reaction
A catalyst provides an alternate pathway of lower activation energy. The same lowered barrier lies between reactants and products in both directions, so a catalyst speeds up the forward and the backward reactions to the same extent. It does not change ΔG or the equilibrium constant; the equilibrium is only reached sooner.
Option (1) The catalyst increases the rate of only the forward reaction — An incorrect statement about a catalyst. Speeding up only the forward reaction would shift the equilibrium, which a catalyst never does.
Option (2) The catalyst increases the rate of both the forward and the backward reaction — A correct statement about a catalyst. The lowered barrier serves both directions.
Option (3) The catalyst decreases the activation energy of the overall reaction — A correct statement about a catalyst. It lowers the potential energy barrier by changing the mechanism.
Option (4) The catalyst itself does not undergo any chemical change — A correct statement about a catalyst. It forms a temporary intermediate but is recovered unchanged at the end.
NCERT (2026-27 edition):
Effect of Catalyst – “… A catalyst does not alter Gibbs energy, ΔG of a reaction. It catalyses the spontaneous reactions but does not catalyse non-spontaneous reactions. It is also found that a catalyst does not change the equilibrium constant of a reaction rather, it helps in attaining the equilibrium faster, that is, it catalyses the forward as well as the backward reactions to the same extent so that the equilibrium state remains same but is reached earlier.”
Note: The same/similar question has been asked in different years by NTA as per the details given below:
| 2026 | 2025 | 2024 | 2023 | 2022 |
|---|---|---|---|---|
| – | – | – | 14-06 S1 11-06 S3 | – |