In the nitration mixture concentrated sulphuric acid is used.

Concentrated sulphuric acid is not

While preparing dilute sulphuric acid from concentrated sulphuric acid in the laboratory, the concentrated sulphuric acid is added slowly to water with constant stirring.

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 ?