Choose the correct statement from the following:

The correct answer is Option (3) → The rate of a reaction is generally accelerated by the presence of a catalyst.

A catalyst increases the rate of a reaction without itself undergoing any permanent chemical change. It provides an alternate pathway (reaction mechanism) with a lower activation energy. By the Arrhenius equation, a lower E_a means a larger rate constant, so the reaction becomes faster at the same temperature.

    \( k = A\,e^{-E_a/RT} \)

Why the other options are incorrect

• Option (1) The presence of a catalyst makes the value of \(\Delta G^o\) more negative. — Incorrect. A catalyst does not alter the Gibbs energy of a reaction. It speeds up the forward and backward reactions to the same extent, so the equilibrium constant also stays the same.

• Option (2) A catalyst does not affect the rate of reaction. — Incorrect. Changing the rate is what a catalyst does; a substance that slows a reaction is called an inhibitor.

• Option (4) A catalyst does not affect the energy of activation \((E_a)\). — Incorrect. A catalyst works by lowering the activation energy; this is why the rate increases.

NCERT (2026-27 edition):
Effect of Catalyst – “A catalyst is a substance which increases the rate of a reaction without itself undergoing any permanent chemical change. … It is believed that the catalyst provides an alternate pathway or reaction mechanism by reducing the activation energy between reactants and products and hence lowering the potential energy barrier as shown in Fig. 3.11. … A small amount of the catalyst can catalyse a large amount of reactants. A catalyst does not alter Gibbs energy, ΔG of a reaction. It catalyses the spontaneous reactions but does not catalyse non-spontaneous reactions.”