What is the difference between Arrhenius, Bronsted-Lowry, and Lewis acids and bases?

1 Answer
Jul 11, 2018

Arrhenius => release of #H^+#/#OH^-# in aqueous solution

Bronsted-Lowry => donation/acceptance of proton

Lewis => acceptance/donation of electron pair


The definition of acid and base according to the three acid-base theories are:

Arrhenius acid-base theory

  • acid - a substance produces hydrogen ions (#H^+#) in aqueous solution.
  • base - a substance that produces hydroxide ions (#OH^-#) in aqueous solution.

Here's the general equation defining Arrhenius acid and base:

Bronsted-Lowry acid-base theory

  • acid - proton (hydrogen ion) donor

  • base - proton (hydrogen ion) acceptor

Here are examples showing general equation defining (a) acid and (b) base:
In (a), HA is an acid since it donates proton(#H^+#) to water. In (b), B is a base because it accepts proton (#H^+#)from water.

Lewis acid-base theory

  • acid - electron pair acceptor

  • base - electron pair donor

An example illustrating Lewis acid-base:

#BH_3# in the given example is a Lewis acid since it accepts the electron pair from #NH_3#
#NH_3#, in this case, is a Lewis base since it donates the electron pair.