Question

On the basis of kinetic theory of gases, the gas exerts pressure because its molecules :

• A. continuously lose their energy till it reaches wall.
• B. continuously stick to the walls of container.
• C. are attracted by the walls of container.
• D. suffer change in momentum when impinge on the walls of container.

Hint:

Gas pressure is a macroscopic manifestation of countless microscopic collisions and the resulting momentum transfer to the walls.

Answer 1

The Correct Option is D

The given question is based on the kinetic theory of gases, which helps us understand the behavior of gas molecules and how they exert pressure within a container.

According to the kinetic theory of gases, the molecules of a gas are in continuous, random motion and frequently collide with each other and the walls of the container. These collisions are elastic, meaning the total kinetic energy and momentum are conserved.

Gas exerts pressure as a result of these collisions. When gas molecules strike the walls of a container, they undergo a change in momentum. This change in momentum upon collision with the walls is what causes the force that we perceive as pressure.

Let's evaluate the options:

• Option 1: Continuously lose their energy till it reaches the wall. - This statement is incorrect as per the kinetic theory because gas molecules do not lose their energy when they are in motion; they only transfer energy during collisions.
• Option 2: Continuously stick to the walls of the container. - This is also incorrect as gas molecules do not stick to the walls; they bounce off due to elastic collisions.
• Option 3: Are attracted by the walls of the container. - This is incorrect as well because there is no significant attractive force acting between the gas molecules and the walls; the primary interaction is through collisions.
• Option 4: Suffer change in momentum when impinge on the walls of the container. - This is the correct answer. The pressure exerted by the gas is due to the change in momentum of molecules when they collide with the container walls.

Therefore, the gas exerts pressure because it suffers a change in momentum when impinging on the walls of the container, as specified by option 4.