Question

give reason for a large volume of gases can be compressed in a small cylinder

Answer 1

......coz gases r highly compressible

Answer 2

The molecules in the gases are not tightly packed.

The molecules are loosely held due to which the movement of the molecules causes some kind of kinetic energy so for a situation where the gas is kept in a cylindrical vessel.

This energy will lead to create a pressure due to which the gas could easily be compressible  and this is also a reason that it is said to be that gas are highly compressible in nature.