Why is hydrogen bond stronger than Van der Walls force?

dipole-dipole interaction is one of the Van Deer Waals force too.

H-bond is a hydrogen which is affected by a negative inductive effect(-I) by a high electronegative element like N,O,F. H will have a strong positive charge.

Because of its positve charge, H will be attracted by high density of eletron cloud like lone pair in a
high electronegative element to from a H-bond

In Van der Waals force.Like dipole-dipole interaction the charge of positive and nagative is weaker than
H which in H-bond because of the different of electronegative is not large enough.

That why Van der Waals force is weaker than H-bond....

Hydrogen gas exist as H2 under room condition.
(i.e. one H2 molecule = two hydrogen atoms)
Between the 2 atoms, there is strong covalent bond.

Van der Waals' forces means the weak attraction between molecules.