Question

Which of the following do not pertain to the postulates of kinetic theory of gases?

• A. The gas molecules are perfectly elastic
• B. Speed of gas molecules are every changing
• C. Pressure exerted by the gas is due to the collision of molecules with the walls of the container
• D. Kinetic energy of a gas is given by the sum of $273$ and temperature in Celsius scale

Answer 1

The correct option is B Speed of gas molecules are every changing

The option (B) do not pertain to the postulates of kinetic theory of gases.
"Speed of gas molecules are every changing."
All that is mentioned in the postulates of kinetic theory of gases is that the molecules are moving very fast in all directions in a straight line until their direction is changed on collision with each other or with the walls of containers. During collisions, there is redistribution of kinetic energy. Nothing is mentioned regarding ever changing speed.
Note:
Kinetic energy of a gas is directly proportional to the absolute temperature which is given by the sum of 273 and temperature in Celsius scale.