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.
38 exam-style questions on Edexcel GCSE Chemistry 5.2 Reversible reactions and equilibria, covering 5.2.1 Reversible reactions and dynamic equilibrium, 5.2.2 The Haber process, and 5.2.3 Changing the position of a dynamic equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.