A hydrogen bond represents a dipolar attraction between a hydrogen atom and another highly electronegative atom. The hydrogen bond is represented by ....
For eg H .... X .... X .... X .....
X = O,N,S,F,Cl...
The bond pair involved in hydrogen bonding was attracted more towards highly electronegative atom, as a result H atom will start acquiring a partial positive charge(δ+) ; the electronegative atom will acquire a partial negative charge( δ−).
The magnitude of H-bonding is maximum in the solid state and minimum in the gaseous state.
Hydrogen bonds are of two types
(i) Intermolecular H-bond e.g., HF, H2O etc.
(ii) Intramolecular H-bond e.g., o-nitrophenol
Vander Waal's forces are weak forces and exist in non-polar compounds and noble gases, as compared to hydrogen bonds they are weak in nature because of strong dipole dipole interaction in hydrogen bonding.