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Chemistry LibreTexts

Lewis Theory

[ "article:topic", "authorname:ggunawardena", "Lewis acid-base" ]
  • Page ID
    39037
  • According to Brønsted-Lowry theory, only a species containing at least one hydrogen atom has the potential to act as an acid in a reaction. Lewis theory is an attempt to extend the concept of acidity beyond species containing hydrogen. According to Lewis theory, in a reaction, a species that accepts a pair of electrons to form a new covalent bond is an acid, and a species that contribute s a pair of electrons toward a new covalent bond is a base.

    eg. 1:

    In this reaction, \(BF_3\) accepts a pair of electrons from \(F^-\) to form a new covalent bond and, therefore, acts as an acid; \(F^-\) contributes a pair of electrons toward a new covalent bond with \(BF_3\) and, therefore, acts as a base.

    In a reaction a species that acts as an acid according to Lewis theory is called a Lewis acid and a species that acts as a base a Lewis base.

    eg. 2: