HYDROGEN BONDING:

 HYDROGEN BONDING:

•Definition:

Hydrogen bond is the attraction between the lone pair of an electronegative atom and a hydrogen atom that is bonded to N,O,or F.

• Example:

Hydrogen bonding is present in NH3, H2O, HF, alcohols and carboxylic acids etc.

• Explanation:

Which one of them have higher boiling point.H2O OR H2S?

The boiling point and heat of vapourization of water are higher than those of H2S because H2O molecules attract each other through H-bonding whereas H2S molecules attract each other by dipole-dipole interactions.

• Limitation:

Hydrogen bonding is mainly limited to participation of nitrogen, oxygen and flourine atom.

• Strength of hydrogen bond:

Hydrogen bonds are stronger than London dispersion forces. Increasing order of strength of attractive forces is;

London dispersion force<dipole-dipole<H-bonding<Covalent bond.