What will happen to the volume of a gas in a closed container if you increase the external pressure?

Question

What will happen to the volume of a gas in a closed container if you increase the external pressure?

Answer 1

Nothing.  The container is closed, so anything we do on the exterior doesn't matter.  The pressure inside the container will be a function of the temperature, the volume, the number of moles of substance, and to a slight degree what the gas itself is.  If you mean like in a piston, however, where the volume of the container can be affected by external pressure, then increasing the pressure will decrease the volume inside the piston.