Define the following and give an example of each:. (a) dispersion force
(b) dipole-dipole attraction
(c) hydrogen bond

London Dispersion force or Van de Waals force is a temporary attractive force which are the weakest and occur between nonpolar noble gases and same charges. This force is weaker because they have more electrons that are farther from the nucleus and are able to move around easier.

Example: ,

Dipole force is present between the polar molecules. Polar molecules are those molecules which have slightly negative and slightly positive charge. Dipole-dipole forces are attractive forces between the positive end of one polar molecule and the negative end of another polar molecule.

Example: HCl, HF,

It is a special type of dipole force present between polar molecules, it is formed between Hydrogen atom which forms positive ion, and the other negative ion. It results from the attractive force between a hydrogen atom covalently bonded to a very electronegative atom such as a N, O, or F atom. The hydrogen bond is one of the strongest intermolecular attractions, but weaker than a covalent or an ionic bond.

Example: Every polar molecule which has hydrogen has hydrogen bonding i.e.