In the industrial Contact process, sulfur trioxide (SO3\text{SO}_3SO3) is produced via the following reversible reaction:
2SO2(g)+O2(g)⇌2SO3(g) 2\text{SO}_2\text{(g)} + \text{O}_2\text{(g)} \rightleftharpoons 2\text{SO}_3\text{(g)} 2SO2(g)+O2(g)⇌2SO3(g)The forward reaction is exothermic.
If sulfur dioxide and oxygen are reacted at a pressure of 1.5 atm and a low temperature of 150 °C without a catalyst, a very high equilibrium yield of sulfur trioxide can theoretically be achieved, but the reaction takes a very long time to reach equilibrium.
In industrial practice, a pressure of 1.5 atm and a temperature of 450 °C are used in the presence of a vanadium(V) oxide catalyst.
Explain why the conditions of 450 °C and a vanadium(V) oxide catalyst are preferred for the profitable manufacture of sulfur trioxide compared to the low-temperature, catalyst-free conditions.
Practise Edexcel GCSE Chemistry Reversible reactions and equilibria with exam-style questions for Foundation and Higher tier. 38 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
