Answer to Question #115381 in General Chemistry for brooke

Question

Explain how the Lewis definition of a base is different from that of the Arrhenius definition of a base. Are Arrhenius bases also bases under the Lewis definition? Explain.

Answer 1

According to Arrhenius, a base dissolves in water and produces OH^- ions. According to Lewis, a base is a molecule that donates an electron pair. Lewis definition is applicable to nonwater solvents, while Arrhenius theory deals with  compounds dissolved in water. Yes, Arrhenius bases are also bases under the Lewis definition because the fact that OH^- forms also indicates that there must be an ion of opposite polarity.