Question

Assertion :The total translational kinetic energy of all molecules of a given mass of an ideal gas is $1.5$ times the product its pressure and its volume. Reason: The molecules of a gas collide with each other and the velocities of the molecules change due to the collision.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason are correct

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

Ideal gas equation,

$PV=nRT$

Total translational kinetic energy
$=\frac{3}{2}nRT=\frac{3}{2}PV$ (by substitution)

So total translational kinetic energy of all molecules of a given mass of an ideal gas is $1.5$ times the product its pressure and its volume.

The molecules are never in stationary state but they are believed to be in chaotic (random) motion. They travel in straight line in all possible directions with altogether different but constant velocities. The direction of motion is changed by the collision with container or with other molecules and their velocity changes after collision.