Question

why intermolecular force of attraction in solid are very strong ?

Answer 1

The molecules of a gas move apart when they collide. The average kinetic energy of the particles in a liquid (or solid) is small enough that the forces of attraction between them is sufficient to hold the particles close together.

Answer 2

well solids r the strongest recognized materials so far because of their intermolecular forces which arise due to very close packing of atoms so that any force operating in an inertial frame decreases on increasing the distance.so if they r closely packed they have very less distance and for instance Vander Wal forces operate to a higher extent