Question

Which of the following statements are correct about solid catalyst?

• A. Catalyst does not change $△H$ of reaction.
• B. Same reactants may give different products by using different catalysts.
• C. Catalytic activity of a solid catalyst does not depend upon the strength of chemisorption.
• D. Catalyst is required in large quantities to catalyse reactions.

Answer 1

Answer: (A), (B)

Same reactants may give different products by using different catalysts.

Same reactants may give different products by using different catalysts. $A$ catalyst is highly selective in nature. For example, during the catalytic hydrogenation of alkyne, if we use Palladium as a catalyst, the product will be alkane. But if hydrogenation is carried out using Lindlar catalyst, we get alkene as a product. So, option $\left(A\right)$ is correct.

Using a catalyst, it does not interfere with the total amount of heat absorbed or released for a chemical reaction. So, the change in enthalpy is independent of the catalyst. Therefore, $\left(B\right)$ is also correct $\left(\text{although it affects the activation energies}\right).$

Catalyst is a substance which is required in very less amount to catalyse any reaction. So, $\left(C\right)$ is wrong.

Chemisorption involves the formation of chemical bonds through which an adsorbate gets adsorbed on adsorbent. So, if the interaction between the reactant molecules is large enough, formation of an activated complex becomes easier using a catalyst. So, $\left(D\right)$ is wrong.