In each of the following questions, a statement I is given followed by a corresponding statement II just below it. Based on the given statements, mark the correct answer.

Statement I: The equilibrium constant does not change on addition of a catalyst.

Statement II: A catalyst provides an alternative path of lower activation energy for conversion of reactants to products.

Both statement I and statement II are true but statement II is not the correct explanation of statement I.

The correct answer is option 2. Both statement I and statement II are true but statement II is not the correct explanation of statement I.

Let us break down and explain each statement in detail, focusing on their correctness and the relationship between them.

Statement I: The equilibrium constant does not change on addition of a catalyst.

This statement is true. The equilibrium constant (\(K\)) for a chemical reaction is determined solely by the temperature and the difference in Gibbs free energy (\(\Delta G^\circ\)) between the reactants and products at equilibrium. The presence or addition of a catalyst does not alter the thermodynamic equilibrium constant because a catalyst:

Speeds up the rate of both the forward and reverse reactions equally.

Does not change the position of equilibrium, meaning it does not affect the relative concentrations of reactants and products once equilibrium is reached.

The equilibrium constant \(K\) remains constant because it reflects the ratio of concentrations of reactants and products at equilibrium, which is determined by the inherent energy differences between them and the temperature.

Statement II: A catalyst provides an alternative path of lower activation energy for conversion of reactants to products.

This statement is true. A catalyst is a substance that speeds up the rate of a chemical reaction by lowering the activation energy (\(E_a\)) required for the reaction to proceed. Here's how a catalyst achieves this:

Lowering activation energy: A catalyst provides an alternative reaction pathway with a lower activation energy barrier. This pathway typically involves the formation of an intermediate complex with the catalyst, which stabilizes the transition state and lowers \(E_a\).

Reaction mechanism: The catalyst participates in the reaction by forming transient bonds with reactants to facilitate their transformation into products. Importantly, the catalyst is regenerated at the end of the reaction and can be used repeatedly.

Relationship Between the Statements:

Statement I addresses the equilibrium constant (\(K\)), which is a thermodynamic property depending only on temperature and the free energy changes of the reactants and products. The addition of a catalyst does not alter these thermodynamic properties.

Statement II describes the kinetic role of a catalyst in providing a lower activation energy pathway for the reaction. This lowers the energy barrier for both the forward and reverse reactions, thereby increasing the rate of the reaction reaching equilibrium.

Both statements I and II are true based on the definitions and roles of catalysts in chemical reactions. Statement II is not the correct explanation of statement I because they describe different aspects of catalysis: statement I pertains to the equilibrium constant, which is a thermodynamic property, while statement II relates to the kinetic role of a catalyst in lowering activation energy. Therefore, the correct answer remains:Both statement I and statement II are true but statement II is not the correct explanation of statement I. This choice accurately reflects that both statements are independently correct, but statement II does not directly explain statement I in terms of their content.