Question

Which of the following is/are true for heterogenous catalysis?

• A. It takes place at the surface of the catalyst rather than at the bulk.
• B. Gas molecules are held up in the bulk due to strong chemical combination.
• C. One gas molecule gets adsorbed at a time without reacting with each another.
• D. None of the above

Answer 1

The correct option is A It takes place at the surface of the catalyst rather than at the bulk.

Mechanism of Heterogenous Catalysis:

The surface of the catalyst unlike the inner part of the bulk, has free valancies which provide the seat for chemical forces of attraction.

Gas molecules are held up on the surface due to loose chemical combination. Different molecules are adsorbed side by side and react with each other forming new molecules.
Formed product molecules may evaporate leaving the surface
for the fresh reactant molecules.
Hence (a) is correct