Question

Write the conditions to maximize the yield of H₂SO₄ by contact process.

Answer 1

Manufacturing of sulphuric acid via the contact process involves three steps:

(1) Burning of ores to form SO₂

(2) Conversion of SO₂ to SO₃ using V₂O₅ as a catalyst

(3) Absorption of SO₃ in H₂SO₄ to give oleum

The second step, i.e. conversion of SO₂ to SO₃ is the key step. Since this reaction is exothermic in nature and two moles of gaseous reactant give one mole of gaseous product. Thus, in accordance with Le Chatelier's principle, to obtain the maximum amount of SO₃, low temperature and high pressure are required.