What is surface tension of liquids? Explain the affect of temperature on the surface tension of liquids.

Explanation

Surface tension property (`gamma`): "It is defined as the force acting along the surface of a liquid at right angles to any line of 1 unit length.
It is numerically and dimensionally equal to surface energy. It has dimensions kg. `s^(-2)` and in SI unit `Nm^(-1)`.

If we consider a molecule in the bulk of the liquid it experiences equal intermolecular forces in all directions. Hence there is no net force acting on it. But a molecule at the surface has intermolecular forces from inside only. Therefore there is a net attractive force on it towards the interior of the liquid. Due to this the surface area of the liquid tends to minimise. That is the molecules experience a downward force and have more energy than the molecules in the bulk Surface tension decreases with increase of temperature because of increase in K E. of molecules and decrease in intermolecular forces.