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Conjugate Acid and Base

Posted: Sun Nov 25, 2018 9:03 pm
by 805132275
Does the concept of conjugate acids and bases only apply to Lewis acid and bases or is it inclusive to bronsted acid and bases?

Re: Conjugate Acid and Base

Posted: Sun Nov 25, 2018 10:35 pm
by armintaheri
I think you have that backwards. The concept of conjugates exists in Bronsted-Lowry, since it deals with proton exchange. An acid loses a proton and becomes its conjugate base, a base gains a proton becomes its conjugate acid. Lewis acids and bases don't always exchange protons. For example, BF3 is a Lewis acid. It can accept an electron pair from F-, which is a Lewis base, and become BF4-. Since there are no protons being gained or lost, the concept of conjugates makes no sense here. It only applies to Lewis acids and bases if they are also Bronsted-Lowry acids and bases, like NH3 and NH4+.