Question

Which one is an example of heterogenous catalysis?

• A. Hydrolysis of sugar catalysed by H+ ions
• B. Decomposition of ozone in-presence of nitrogen monoxide
• C. Combination between dinitrogen and dihydrogen to form ammonia in the presence of finely divided iron
• D. Oxidation of sulphur dioxide into sulphur trioxide in the presence of oxides of nitrogen

Answer 1

The Correct Option is C

The correct example of heterogeneous catalysis is the combination between dinitrogen (N₂) and dihydrogen (H₂) to form ammonia (NH₃) in the presence of finely divided iron.

In heterogeneous catalysis, the catalyst is in a different phase from the reactants. In this reaction, nitrogen and hydrogen are gases, whereas iron is a solid catalyst, distinguishing it as a heterogeneous system.

The reaction can be represented as follows: 

N₂(g) + 3H₂(g) ⇌ 2NH₃(g)

The finely divided iron provides a surface for the gas molecules (N₂ and H₂) to adsorb, facilitating their reaction to form ammonia.

Answer 2

Heterogeneous catalysis refers to a catalytic process where the catalyst exists in a different phase (usually solid) from the reactants and products (usually gas or liquid phases). In option C, the reaction between dinitrogen and dihydrogen to form ammonia is catalyzed by finely divided iron, which is a solid catalyst. The reactants (dinitrogen and dihydrogen) are in the gas phase, while the catalyst (finely divided iron) is in the solid phase, making it an example of heterogeneous catalysis.

The correct option is (C): Combination between dinitrogen and dihydrogen to form ammonia in the presence of finely divided iron