Given below are two statements :
Statement I : A catalyst cannot alter the equilibrium constant (K_c) of the reaction, temperature remaining constant.
Statement II : A homogenous catalyst can change the equilibrium composition of a system, temperature remaining constant.
In the light of the above statements, choose the correct answer from the options given below

Solution

Chemistry ma’am · 4 steps

A catalyst speeds up both directions equally, so it gets you to equilibrium faster but never moves it.

1. What a catalyst does. A catalyst offers a new path with a lower activation energy. It lowers the barrier by the same amount for the forward and the backward reaction, so k_f and k_b go up by the same factor.

   K_c = k_f/k_b

2. Statement I. Both rate constants are multiplied by the same factor, so their ratio K_c stays the same. K_c depends only on temperature, so Statement I is true.
3. Statement II. At a fixed temperature the equilibrium composition is set by K_c. A homogeneous catalyst does not change K_c, so it cannot change the amounts present at equilibrium. It only helps the system reach them sooner. Statement II is false.
4. So. Statement I is true and Statement II is false, which is option (a).

The idea to keep. A catalyst changes how fast you reach equilibrium, never where equilibrium lies. Homogeneous or heterogeneous, K_c and the equilibrium composition are fixed by temperature alone.

Answer from the NTA final answer key. Solution by PrepWiser.