A gas exerts pressure on the walls of the container Why

A gas exerts pressure on the walls of the

container Why ? . 

Answer - Because of negligible force of attraction between particles of gas, the particles of gas have the highest kinetic energy. 

These properties enable the particles of gas to move in all directions and hit

the walls of container from all sides. Because of this a gas exerts pressure on the walls of the container in which it is kept.