Page 63 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1

Mansoura National University
Pharm D-Clinical Pharmacy Program Level 1 Pharm. Anal. Chem. 1 (PC 101)

3. Lewis Theory

Lewis focused on electron transfer instead of proton transfer.

▪ A Lewis acid is a substance that ▪ A Lewis base is a substance that can

can accept a pair of electrons to donate a pair of electrons to form a

form a covalent bond. covalent bond.

▪ Neutralization is the immediate formation of a coordinate covalent bond
between an acid and base.

• This theory explains:

(A) Acid-base reactions that proceed in non-aqueous medium.

+
(B) Presence of substances that do not contain H and considered acids and presence

-
of substances that do not contain OH and considered bases.

Example of Lewis acids: AlCl , Boron trichloride {BCl }
3 3
Example of Lewis bases: NH , Triethanol amine {(C 2H 4OH) N}
3 3

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