Hydrogen bonding is a special form of dipole-dipole interaction. In some molecules containing hydrogen atoms, because of differences in electronegativities, hydrogen can be left with a slightly positive charge and the other element with a slightly negative charge.
Although a hydrogen bond is much stronger than an ordinary dipole-dipole force, it is roughly one-tenth as strong as a covalent bond between atoms of the same two elements. A hydrogen bond is about 10 percent of the typical strength of the covalent bond, making it much more attractive than the dipole-dipole and London dispersion.
For example, the boiling points of alcohols are higher as compared to the boiling point of alkyl halides of comparable molecular mass. Hydrogen bonding in alcohol is stronger than dipole-dipole interactions in alkyl halides.