Hydrogen gas is evolved dilute hydrochloric acid is added to a reactive metal.
When iron reacts with dilute
H2SO4
.
iron (II) sulphate with the evolution of hydrogen gas is formed.
Fe(s)+H2SO4(aq)→FeSO4(aq)+H2(g)

When dilute hydrochloric acid reacts with a reactive metal, hydrogen gas (H₂) is produced. The chemical reaction when iron reacts with dilute sulfuric acid (H₂SO₄) is: Fe(s) + H₂SO₄(aq) → FeSO₄(aq) + H₂(g).
Explanation:
Hydrogen gas is produced: when a reactive metal (like iron) reacts with a dilute acid (like hydrochloric acid or sulfuric acid).
The reaction between iron and dilute sulfuric acid: results in the formation of iron(II) sulfate (FeSO₄) and hydrogen gas.