Question

Concentrated sulphuric acid is a strong oxidising agent and a dehydrating agent, but not in its dilute form. Explain.

Answer 1

Part 1: Oxidising Property of Sulphuric Acid $\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)$:

1. Concentrated Sulphuric acid acts as a strong oxidizing agent because on heating, concentrated Sulphuric acid decomposes to give nascent oxygen $\left[\mathrm{O}\right]$ which makes a strong oxidizing power.
2. Hence, it cannot act as an oxidizing agent.

Part 2: Dehydrating Property of Sulphuric Acid:

1. Concentrated Sulphuric acid can also act as a dehydrating agent because it has a great affinity for water.
2. Dilute Sulphuric acid has no affinity for water because already it contains a large amount of water around it.
3. Therefore, it cannot act as a dehydrating agent.