Question

A liquid is in equilibrium with its vapour at its boiling point. On an average of the molecules in two phases which of the following is equal ?

(A) Potential energy

(B) Total energy

(C) Kinetic energy

(D) Intermolecular force

Answer 1

Correct option is (C) Kinetic energy

According to kinetic theory, average kinetic energy \((\epsilon) = \frac 32 k_BT\).

Where, k_B is Boltzmann's constant. Thus, kinetic energy is directly proportional to temperature.

When the liquid is in equilibrium with its vapour pressure at its boiling point, the molecules in two phases have same kinetic energy as they are at same temperature.