There are two types of molecular forces: adhesive force and cohesive force.

Adhesive Force:

It is the force of attraction between the molecules of different substances and is different for different pairs of substances.

Cohesive Force:

It is the force of attraction between the molecules of the same substance. This force is different from the ordinary gravitational force of attraction and does not obey the ordinary inverse square law. This force varies inversely probably as the eight power of the distance between the molecules and thus decreases rapidly with distance.