What pressure is required for the manufacture of sulfuric acid by the contact process?

The pressure required for the manufacture of sulfuric acid by the contact process typically ranges around 2 atm. This pressure is advantageous because the contact process involves the oxidation of sulfur dioxide (SO₂) to sulfur trioxide (SO₃) using a vanadium(V) oxide catalyst. While the reaction itself is not significantly affected by pressure, operating at around 2 atm can help increase the rate of reaction and improve the yield of sulfur trioxide gas, which is crucial for sulfuric acid production.

Higher pressures may not provide significant benefits to the reaction, given that the reaction produces a gas with no change in the total number of moles of gas (3 moles of reactants yield 3 moles of products), according to Le Chatelier's principle. Therefore, a moderate increase in pressure to 2 atm proves to be effective for maximizing the overall efficiency and productivity of the sulfuric acid manufacturing process.