Question

why do gas exert pressure​

Answer 1

The molecules are continually colliding with each other and with the walls of the container. When a molecule collides with the wall, they exert small force on the wall The pressure exerted by the gas is due to the sum of all these collision forces.The more particles that hit the walls, the higher the pressure

Answer 2

Because the molecules are colloids with each other when the molecules are colloids with wall they generate

Small force on wall and these small force create pressure