Question

Hydrogen chloride gas is prepared in the laboratory using concentrated sulphuric acid and sodium chloride. Answer the question that follow based on this reaction.

Why is concentrated sulphuric acid used instead of concentrated nitric acid?

Answer 1

As conc. H₂SO₄ is non-volatile and has a high boiling point; therefore, it displaces the volatile hydrogen chloride from the salt sodium chloride. Hence, conc. H₂SO₄ is used as a reactant in the laboratory preparation of HCl from sodium chloride. Conc. nitric acid cannot be used in place of conc. H₂SO₄ since it is volatile and may volatilize out along with the hydrogen chloride.