On what does the value of surface tension depend? Explain.

The value of surface tension depends primarily on the temperature of the liquid.
As the temperature increases, the kinetic energy of the molecules increases, which weakens the intermolecular forces of attraction. Consequently, the surface tension of a liquid decreases as the temperature rises.
At the critical temperature, the distinction between the liquid and vapor phases disappears, and the surface tension becomes zero.
Surface tension is also influenced by the presence of impurities (solutes) in the liquid. Solutes that decrease the cohesive forces between liquid molecules reduce surface tension, while those that increase cohesive forces raise it.
Below is a table showing the surface tension of various liquids at specific temperatures:

Liquid	Temp. $(^{\circ}C)$	Surface tension $(N/m)$	Heat of vaporization $(kJ/mol)$
Helium	$-270$	$0.000239$	$0.115$
Oxygen	$-183$	$0.0132$	$7.1$
Ethanol	$20$	$0.0227$	$40.6$
Water	$20$	$0.0727$	$44.16$
Mercury	$20$	$0.4355$	$63.2$