Question

explain the concave and convex surface of liquid on the basis of molecular forces​

Answer 1

When liquid water is confined in a tube, its surface (meniscus) has a concave shape because water wets the surface and creeps up the side.

Answer 2

ANSWER

Surface tension is measured as the energy required to increase the surface area of a liquid by a unit of area. The surface tension of a liquid results from an imbalance of intermolecular attractive forces, the cohesive forces between molecules:

A molecule in the bulk liquid experiences cohesive forces with other molecules in all directions.

A molecule at the surface of a liquid experiences only net inward cohesive forces.

A microscopic view of water illustrates the difference between molecules at the surface of a liquid and water molecules within a liquid