Describe the manufacture of H2SO4 by contact process

Describe the manufacture of H₂SO₄ by contact process? 

Answer

Sulphuric acid is manufactured by the contact process. It involves the following steps:

This oleum is then diluted to obtain H₂SO₄ of the desired concentration.
In practice, the plant is operated at 2 bar (pressure) and 720 K (temperature). The sulphuric acid thus obtained is 96-98% pure.