Statement I: The rate of reaction can also increase with increase in conc. of its product if one of the products acts as catalyst

Statement II: A catalyst lowers the activation energy of reactants.

Statement I and statement II are correct but statement II is not the correct explanation of statement I

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

Statement I: The rate of reaction can also increase with an increase in the concentration of its product if one of the products acts as a catalyst.

Normally, increasing the concentration of a reactant speeds up the reaction because it leads to more frequent collisions between reactant molecules. 

However, if one of the products acts as a catalyst, increasing its concentration can also speed up the reaction. This is because the product may participate in the reaction mechanism as a catalyst, facilitating the conversion of reactants to products.

Example: In the case of the iodination of acetone, iodide ions (which can be products or intermediates in certain conditions) can act as catalysts by participating in a reaction step that accelerates the overall process.

Statement II: A catalyst lowers the activation energy of reactants.

A catalyst works by providing an alternative pathway for the reaction with a lower activation energy. This allows the reaction to proceed faster because less energy is required for the reactants to reach the transition state. The catalyst itself is not consumed in the reaction and can be reused multiple times.

Relationship Between the Statements:

Statement II is a general principle about how catalysts work. It explains the fundamental mechanism by which catalysts increase reaction rates by lowering activation energy.

Statement I is a specific scenario where a product of a reaction can also act as a catalyst. In this case, the product helps to speed up the reaction, potentially increasing the rate even when it is not initially expected.

Connection and Explanation:

Statement II explains the general principle of how catalysts influence reaction rates by lowering activation energy. Statement I describes a specific case where the product of a reaction may act as a catalyst, which can influence the reaction rate.

Why Statement II is not the correct explanation for Statement I:

While Statement II provides a general principle about catalysts, it does not specifically address the scenario where a product of the reaction also acts as a catalyst. Statement I describes a situation where a product may act as a catalyst, but this scenario is a specific instance and does not rely solely on the general principle of lowering activation energy.

Therefore, the correct relationship is: Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I.