Question

what happens to the pressure of a gas inside a rigid container if the temperature of the gas is lowered

Answer 1

What happens to the molecules of the gas when the temperature is lowered?

Answer 2

just use ideal gas law \[PV=nRT\] and you can see that pressure is proportional to the temperature, as soon as you will start giving heat energy to the container, molecules will gain energy and will expand hence expansion causes increase in pressure , but here the concept is reverse , lowering temp will lower the pressure :)