Definitions of acid and base

 

Traditional approach

Acid: a substance that has certain properties

(eg sour taste, turns litmus red)

Arrhenius approach 

Acid : H+ in aqueous solution

Base : OH- in aqueous solution

• At neutrality: [H+] = [OH-]

Bronsted-Lowry approach

Acid : H+ donor

Base : H+ acceptor

• Conjugate acid-base pairs
• No concept of neutrality

Lewis approach

Acid : a potential electron-pair acceptor

Base : a potential electron-pair donor

Usanovich  apporach

Acid: a substance that donates a cation, or accepts an anion or an electron

Base: a substance that donates an anion, or accepts a cation

 

Other notes