Consider the following statements 1 The surface tension of a liquid is a measure of the su...........

General Science (Easy) Physics

Consider the following statements :

1) The surface tension of a liquid is a measure of the surface energy stored per unit area of the liquid surface

2) Surface tension of a liquid increases with the rise in temperature.

3) The potential energy of a molecule on the surface of a liquid compared to that of a molecule inside the liquid is greater.

Which of these statements is /are correct ?

1 and 2

2 only

1 and 3

1, 2 and 3

Only statements 1&3 are correct.

Statement 1st is correct: Surface tension=Surface energy per unit area. Thus, surface tension is equal to the mechanical work done per unit surface area of the liquid, which is also called as surface energy.
Statement 2nd is incorrect: The magnitude of the surface tension of a liquid depends on the attractive forces between the molecules. When the attractive forces are large, the surface tension is large. An increase in temperature increases the kinetic energy of the molecules, and the effectiveness of intermolecular attraction decreases. So the surface tension decreases as the temperature is raised.
Statement 3rd is correct: When the surface area of the liquid is increased molecules from the interior of the liquid rise to surface . As these molecules reach the surface work is done against the cohesive force.This work is stored in the molecules in the form of potential energy .Thus , the potential energy of the molecules lying in the surface is greater than that of the molecules in the interior of the liquid.