Question

Explain why high pressure is required in the manufacture of sulphur trioxide by the contact process. State the law or principle used. 

Answer 1

This is because the forward reaction is accompanied by a decrease in volume.
The principle used is i.e., Chatelier’s principle.
It states that when a system in equilibrium is subjected to stress, (i.e., change of concentration, temperature pressure etc.), the equilibrium tends to shift in a direction so as to undergo the effect of applied stress.