Question

Neglecting gravity, the potential energy of a molecule of a liquid on the surface of a liquid, when compared to the potential energy of a molecule inside a liquid, is:

• A. greater
• B. lesser
• C. equal
• D. depending upon the liquid, some times more, some times less

Answer 1

The correct option is A greater

At liquid-air interface, there is greater attraction of water molecules to each other (due to cohesion) than to the molecules in the air. The net effect is an inward force at its surface that causes an increase in potential energy of the surface molecules.