What kind of bond are hydrogen bond?

Answer 1

Hydrogen bonds are predominantly electrostatic interactions between a weakly acidic donor group and an acceptor atom that bears a lone pair of electrons. Hydrogen bonds are categorized as weak bonds. Hydrogen bonds are usually represented as D-H . . . A, where D-H is a weakly acidic "donor group" such as N-H or O-H, and A is a lone-pair bearing and thus weakly basic "acceptor atom" such as N or O.

In biological systems, hydrogen bonds have association energies in the range -12 to -30 kJ mol-1, are much more directional than van der Waals forces although less than covalent bonds. The distance of D . . . A is normally in the range 2.7 to 3.1 angstroms.