Acid–base reaction models as theories that complement each other. For example the current Lewis model has the broadest definition of what an acid and base are, with the Bronsted-Lowry theory being a subset of what acids and bases are, and the Arrhenius theory being the most restrictive. The first scientific concept of acids and bases was provided by Lavoisier in around 1776. Since Lavoisier's knowledge of strong acids was mainly restricted to oxoacids, such as (nitric acid) and (sulfuric acid), which tend to contain central atoms in high oxidation states surrounded by oxygen, and since he was not aware of the true
Brønsted–Lowry acid–base theory conjugate acid of the base in the first reaction and the conjugate base of the acid. In the above example, acetate is the base of the reverse reaction and hydronium ion is the acid. The power of the Brønsted–Lowry theory is that, in contrast to Arrhenius theory, it does not require an acid to dissociate. The essence of Brønsted–Lowry theory is that an acid only exists as such in relation to a base, and "vice versa". Water is amphoteric as it can act as an acid or as a base. In the image shown at the right one molecule of