Answer:
Hydrogen bonding.
Explanation:
Nitrogen has 5 valence electrons so it has to share 3 pairs of electrons to reach the octet. Each hydrogen has 1 valence electron, so it has to share 1 pair of electrons to reach the duet. As a result, in the Lewis structure of ammonia, N forms 3 single covalent bonds, one with each H, and has a lone pair. According to VESPR, NH₃ has a trigonal pyramidal shape, thus a net dipole moment. Since the N atom is much more electronegative than the H atom, NH₃ molecules attract each other through hydrogen bondings. This is one of the strongest intermolecular attractions, so it is expected to have a higher boiling point than molecules without hydrogen bondings.
