# What defines an acid and base?

Apr 18, 2016

See below.

#### Explanation:

According to the definition of Brønsted-Lowry, an Acid is a molecule that is capable to donate a proton ${H}^{+}$ in solution, and a Base is a molecule that is capable of accepting an ${H}^{+}$ ion.

A general reaction for an acid dissociation in water is:
$H A \left(a q\right) + {H}_{2} O \left(l\right) \to {H}_{3} {O}^{+} \left(a q\right) + {A}^{-} \left(a q\right)$

A general reaction of a base with an acid is:
$B \left(a q\right) + {H}^{+} \left(a q\right) \to B {H}^{+} \left(a q\right)$

For more details on acids and bases, please watch this video:
Acids & Bases | Nature, Strength & pH Scale.