How does copper react with concentrated sulphuric acid?

Copper does not react with dilute sulphuric acid, but it reacts with hot concentrated sulphuric acid, which acts as a strong oxidizing agent.

Chemical Reaction:

Cu + 2H₂SO₄ (conc.) → CuSO₄ + SO₂ + 2H₂O

What happens in this reaction?

• Copper (Cu) is oxidized to Cu²⁺ ions, forming copper sulphate (CuSO₄).
• Sulphuric acid (H₂SO₄) is reduced to sulphur dioxide (SO₂) gas.
• Water (H₂O) is also produced.

Observations:

• A blue solution of copper sulphate is formed.
• A pungent smell of sulphur dioxide (SO₂) gas is released.
• The reaction requires heating (it doesn’t occur at room temperature).

Key Concept:

Concentrated sulphuric acid behaves as an oxidizing agent, unlike dilute acid, which is why it can react with less reactive metals like copper.

Key Takeaway:

Copper reacts with hot concentrated sulphuric acid to form copper sulphate, sulphur dioxide gas, and water, demonstrating the oxidizing nature of the acid.