Physics - Fluid Question with Solution | TestHub

With a rise in temperature, the kinetic energy of the liquid molecules increases. This increased thermal agitation weakens the intermolecular forces of attraction (cohesive forces) between the molecules.

Since surface tension is a direct consequence of these cohesive forces, a decrease in the cohesive forces leads to a decrease in surface tension.

Therefore, in most liquids, the surface tension decreases with an increase in temperature and becomes zero at the critical temperature.

Answer: decreases.