When H2SO4 reacts with iron sulphate, also known as ferrous sulphate or iron(II) sulphate, the following reaction occurs:

H2SO4 + FeSO4 → Fe2(SO4)3 + H2O

In this reaction, H2SO4, which is a strong acid, donates two protons (H+) to FeSO4, which is a salt containing Fe(II) ions. The Fe(II) ions then combine with the sulphate (SO42-) ions from both H2SO4 and FeSO4 to form iron(III) sulphate [Fe2(SO4)3], which is a more stable compound.

The products of this reaction are iron(III) sulphate, which is a reddish-brown, crystalline solid, and water (H2O). The reaction is typically carried out in aqueous solutions, where the H2SO4 and FeSO4 are dissolved in water before mixing.