The potential energy between two point charges approaches zero more rapidly than the potential energy between a point dipole and a point charge as the distance between them approaches infinity.

The average potential energy of two rotating polar molecules that are separated by a distance r has $1/r^3$ dependence.

The dipole-induced dipole average interaction energy is independent of temperature.

Nonpolar molecules attract one another even though neither has a permanent dipole moment.

H₃PO₄

H₃PO₃

H₄P₂O₇

H₃PO₂

Both X and Y are oxygen containing compounds.

Y on heating with CHCl$_3$/KOH forms isocyanide.

Z reacts with Hinsberg’s reagent.

Z is an aromatic primary amine.