# Is HCl is a strong base or acid?

Jul 3, 2016

$\text{HCl}$ (hydrochloric acid) is a strong acid.

#### Explanation:

Why $\text{HCl}$ is an acid can be explained on basis of many theories, like Arrhenius theory, Bronsted-Lowry acid base theory, and Lewis acid-base theory.

According to Arrhenius theory, a compound which when dissolved in water dissociates and furnishes ${\text{H}}^{+}$ ions is an Arrhenius acid.

According to Bronsted-Lowry theory of conjugated acid-base pairs, the ${\text{H"_3"O}}^{+}$ forms a conjugate base which is water (weakly basic). So $\text{HCl}$ is a Bronsted acid because it donated an ${\text{H}}^{+}$ to water.

According to Lewis Theory, any compound which can accept lone pair of electrons from a donor atom/molecule/group is an acid.
${\text{H}}^{+}$ being a cation easily accepts lone pair of electrons.

So $\text{HCl}$ dissolved in water forms a Lewis acid.

Therefore, $\text{HCl}$ is a strong acid as it readily and easily dissociates in water and furnishes ${\text{H}}^{+}$ ions. The dissociation is 99.9%, which makes it a strong acid.