What are cohesive forces?

Explain surface tension in the context of potential energy.

Why does the surface of a liquid have a tendency to minimize its area?

Define the surface of a liquid.

Explain why:
$(a)$ The angle of contact of mercury with glass is obtuse,while that of water with glass is acute.
$(b)$ Water on a clean glass surface tends to spread out while mercury on the same surface tends to form drops. (Put differently,water wets glass while mercury does not.)
$(c)$ Surface tension of a liquid is independent of the area of the surface.
$(d)$ Water with detergent dissolved in it should have small angles of contact.
$(e)$ $A$ drop of liquid under no external forces is always spherical in shape.

Three surfaces of liquid are shown here. Find the correct statements.