Question

Which of the following is not correct for heterogeneous catalysis ?

• A. The catalyst decreases the energy of activation
• B. The surface of catalyst plays an important role
• C. The catalyst actually forms a intermediate compound with reactants
• D. There is no change in the energy of activation

Answer 1

The correct option is D There is no change in the energy of activation

Catalyst is a substance that lowers the activation energy of reaction because it provides an alternate pathway for reaction. Also, it increases the rate of backward and forward reactions to the same extent. Due to this lower activation energy, equilibrium attains faster but it doesn't change overall enthalpy of reaction.

Heterogeneous catalysis refers to the form of catalysis where the phase of the catalyst differs from that of the reactants. Here, the surface of the catalyst unlike the inner part of the bulk, has free valancies which provide the seat for chemical forces of attraction. The catalyst forms temporary bonds with the reactants resulting in an intermediate complex. ​This exists for a short time ​and decomposes to yield ​products and the catalyst.

Hence, option (d) is the incorrect statement. ​