Question

What is hydrogen bonding? In which compounds hydrogen bonding is maximum? What are the conditions of hydrogen bonding?

Answer 1

We know that Hydrogen bonding is the formation of Hydrogen bonds, which are attractive intermolecular forces. It is found that these arise due to the dipole-dipole interaction between a hydrogen atom which is bonded to a highly electronegative atom and another highly electronegative atom while lies in the vicinity of the hydrogen atom.

Complete answer:
- We can see that in a molecule, when a hydrogen atom is attached to another highly electronegative atom, then it attracts the shared pair of electrons towards itself and therefore this end of the molecules becomes negative whereas the other end becomes slightly positive. Then the negative end of one molecule is found to attract the positive end of the other molecule. And hence, a weak bond is formed between them that is called a hydrogen bond.
- Now we will discuss about the compounds in which hydrogen bonding is maximum:
(i) Hydrogen Bonding in Hydrogen fluoride- It is found that Fluorine forms the strongest hydrogen bond, as it is having the highest value of electronegativity.
(ii) Hydrogen Bonding in Water- As we know that water molecule has a highly electronegative oxygen atom attached to the hydrogen atom. Basically oxygen atom attracts the shared pair of electrons towards itself and this end of the molecule becomes negative, while the hydrogen atoms become positive.
-Now, we will discuss about the conditions for hydrogen bonding:
(i)The important condition is that the molecule must have a highly electronegative atom connected to the hydrogen atom. It is found that higher the electronegativity of the molecule, more is the polarization.
(ii)The second condition is that the size of the electronegative atom must be small. As smaller the size of an atom, more is the electrostatic force of attraction.

Note: - We should not get confused in between the terms Intermolecular Hydrogen Bonding and Intramolecular Hydrogen Bonding. As Intermolecular Hydrogen Bonding takes place between different molecules of the same or different compounds. For example – hydrogen bonding in alcohol, water.
- Whereas, Intramolecular Hydrogen Bonding takes place within a molecule itself. Here, bond formation takes place between the hydrogen atoms of one group with the more electronegative atom of the other group.