Hydrogen Bonding
Hydrogen bond is a type of dipole-dipole interaction between very high electronegative atom (i.e. N, O and F) and a hydrogen atom bonded to another electronegative atom. This bond always involves a hydrogen atom. Hydrogen bonds can occur between molecules or within a single molecule.
Hydrogen bond is stronger than van der Waals forces, but weaker than covalent bonds or ionic bonds. It is about 5% the strength of the normal covalent bond formed between O-H.
Types of Hydrogen Bonding
There are two types of Hydrogen bonds. They are-
1. Intermolecular Hydrogen Bonding
2. Intramolecular Hydrogen Bonding
1. Intermolecular Hydrogen Bonding:
When hydrogen bonding takes place between different molecules of the same or different compounds, it is called intermolecular hydrogen bonding. For example – hydrogen bonding in water, alcohol, ammonia, p-nitrophenol etc.
2. Intramolecular Hydrogen Bonding:
The hydrogen bonding which takes place within a molecule itself is called intramolecular hydrogen bonding.
It takes place in compounds containing two groups such that one group contains hydrogen atom linked to an electronegative atom and the other group contains a highly electronegative atom linked to a lesser electronegative atom of the other group. The bond is formed between the hydrogen atoms of one group with the more electronegative atom of the other group.
For example – ortho-nitrophenol, Salicylic acid, Salicyldehyde etc.
