Question

A liquid is in equilibrium with its vapour at its boiling point. On average, the molecules in the two phases have equal:

• A. Intermolecular forces
• B. Potential energy
• C. Kinetic energy
• D. Kinetic and potential energy

Answer 1

The correct option is C Kinetic energy

The average kinetic energy is proportional to temperature ,
K.E = $\frac{3}{2}{k}_{B}T$
where $k_B$ is Boltzmann's constant.
When the liquid is in equilibrium with its vapour, molecules in the two phases have the same kinetic energy as they are at the same temperature.