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

To determine which option is an example of heterogeneous catalysis, we need to understand the concept of catalysis and its types:

• Catalysis refers to the process in which the rate of a chemical reaction is increased by a substance called a catalyst.
• Heterogeneous catalysis occurs when the phase of the catalyst differs from the phase of the reactants. Commonly, this involves solid catalysts interacting with gaseous or liquid reactants.

Let's analyze each option:

1. Hydrolysis of sugar catalysed by H⁺ ions: This is an example of homogeneous catalysis because both the H⁺ ions and the sugar are in the same phase (aqueous solution).
2. Decomposition of ozone in the presence of nitrogen monoxide: This is homogeneous catalysis as both ozone and nitrogen monoxide are gases, sharing the same phase.
3. Combination between dinitrogen and dihydrogen to form ammonia in the presence of finely divided iron: Here, iron acts as a catalyst that is in a different phase (solid) from the dinitrogen and dihydrogen reactants (gases). This is a classic example of heterogeneous catalysis, as seen in the Haber process.
4. Oxidation of sulphur dioxide into sulphur trioxide in the presence of oxides of nitrogen: This would typically involve gaseous reactants and catalyst, so it is homogeneous catalysis.

Thus, the correct answer is the Combination between dinitrogen and dihydrogen to form ammonia in the presence of finely divided iron, as this involves a solid catalyst and gaseous reactants, a hallmark of heterogeneous catalysis.