State the magnitude of dipole-dipole forces and the value of interaction energy with examples.

(N/A) Dipole-dipole forces: $1$ to $3 \, kcal \, mol^{-1}$.
Examples: $SO_2, NO, HCl$.
For rotating molecules, the interaction energy is proportional to $\frac{1}{r^6}$.
For stationary molecules, the interaction energy is proportional to $\frac{1}{r^3}$.
These forces exist only when the distance between molecules is less than $500 \, pm$.