Amines are basic in nature as they have a lone pair of electrons on nitrogen.

Amines are organic compounds that contain a nitrogen atom bonded to one or more alkyl or aryl groups. They are derived from ammonia (NH3) by replacing one or more hydrogen atoms with alkyl or aryl groups. Amines can be classified as primary, secondary, or tertiary depending on the number of alkyl or aryl groups attached to the nitrogen atom.

Lone pair of electrons on nitrogen:
The basic nature of amines is attributed to the presence of a lone pair of electrons on the nitrogen atom. Nitrogen is a member of Group 15 in the periodic table and has five valence electrons. In the formation of amines, one of the valence electrons of nitrogen is used to form a covalent bond with a hydrogen atom, leaving behind a lone pair of electrons.

The lone pair of electrons on the nitrogen atom is not involved in bonding and is available for donation. This lone pair can act as a Lewis base and can readily accept a proton (H+) from an acid to form a dative bond. This ability to accept a proton makes amines basic in nature.

Basicity of amines:
The lone pair of electrons on the nitrogen atom of amines can interact with hydrogen ions (protons) present in acidic solutions. The nitrogen atom donates its lone pair of electrons to form a coordinate bond with the hydrogen ion, resulting in the formation of an ammonium ion (NH4+).

This protonation of the amine molecule increases the concentration of positive charges on the nitrogen atom, making it more electron-attracting. Consequently, the lone pair of electrons becomes less available for donation, reducing the basicity of the amine.

Conclusion:
In summary, amines are basic in nature due to the presence of a lone pair of electrons on the nitrogen atom. This lone pair can act as a Lewis base and readily accept a proton to form an ammonium ion. The basicity of amines decreases upon protonation as the lone pair of electrons becomes less available for donation.