In industry, the reaction is done at 450 °C and atmospheric pressure. Under these conditions the yield of sulfur trioxide is 86%.
Suggest two reasons why a higher pressure is not used.

Industrial chemical processes are always a compromise between factors that affect the rate of reaction, the percentage yield, and the cost. While Le Chatelier's principle tells us that a high pressure would favour a higher yield of sulfur trioxide, there are significant economic and safety reasons for not using excessively high pressures. 1. **Cost of Energy:** Compressing gases to high pressures requires powerful pumps, which consume large amounts of electrical energy. This adds a significant operational cost to the process. 2. **Cost of Equipment:** The reactor, pipes, and valves must be built to be extremely strong and durable to safely contain gases at high pressure. This requires thick steel and specialised engineering, making the plant very expensive to build and maintain. 3. **Safety:** Operating at high pressures increases the risk of explosions or leaks if the equipment fails. While safety systems are in place, lower pressures are inherently safer. Therefore, a compromise pressure is used that gives a reasonably high yield and rate without making the process prohibitively expensive or dangerous.