Chemistry- Lewis Concept Of Acids And Bases.

Explain the Lewis concept of acids and bases.

A Lewis acid is, therefore, any substance, such as the H+ ion, that can accept a pair of nonbonding electrons. In other words, a Lewis acid is an electron-pair acceptor.

However, hydrogen chloride, acetic acid, and most other Brønsted-Lowry acids cannot form a covalent bond with an electron pair and are therefore not Lewis acids.

A Lewis base is any substance, such as the OH- ion, that can donate a pair of nonbonding electrons.For example, OH− and NH3 are Lewis bases

While the Brønsted-Lowry theory is based on the transfer of protons, Lewis' theory is based on the transfer of electrons. A Lewis acid is a substance that can accept a pair of electrons to form a new bond.

They are sometimes referred to as electrophiles or seekers of an additional electron pair.

NOTE:

HF is the weak acid because of it's strong H-F bond. Fluorine being small in size overlaps better with 1s orbital of hydrogen leading to a strong bond. Hence can not give proton easily. Here bond strength overweighs the electronegativity of F. H-F bond is the weakest of all, so it is the strongest acid.