According to the kinetic theores of gases.
The molecules of a gas are in continuous random motion because gas is not a fin state.
The molecules do not interact or in contact with each othes ercept collisions.
It is experimentally proved that the collisions amongst the molecules are of short duration. because collisions occurs very East.
but the statement that the molecule Continously undergo inelastic collision is wrong or incorrect. Because it is not must that collision be elastic or inelastic, It is depend on the conditions.