2 SO2(g) ⇌ O2(g) + 2 SO3(g) + heat

Question

What will happen if the temperature is decreased?

Answer 1

Le Chatelier's Principle says, in most unsophisticated language, that a system in equilibrium will try to undo what we do to it. So if we take the heat away, the system will try to replace the heat. How can it do that? Obviously, if the reaction produces heat it will replace it by shifting to the right. That will reduce SO2 and produce more O2 and SO3 and heat.