Question

At what temperature the surface tension of a liquid becomes zero?

Hint:

The critical temperature is the point where a substance can no longer be liquefied by pressure alone. Think of it as the temperature where the liquid and gas states merge.

Answer 1

The surface tension of a liquid becomes zero at its critical temperature. At this temperature, the distinction between the liquid and gas phases disappears, and the intermolecular cohesive forces that cause surface tension become negligible.