# Question #b54aa

May 2, 2017

A Bronsted-Lowry base.

#### Explanation:

An Arrhenius base is a species than ionises in water to produce $O {H}^{-}$ ions. Since $C a C {O}_{3}$ contains no $O {H}^{-}$ at all, it does not fulfil the definition of an Arrhenius base.

On the other hand, a Bronsted-Lowry base is a species that can accept a proton or ${H}^{+}$ ion from a Bronsted-Lowry acid. The carbonate ion is able to take in protons to firstly form the bicarbonate ion and then form carbonic acid.

$C {O}_{3}^{2 -} + {H}^{+} \to H C {O}_{3}^{-}$
$H C {O}_{3}^{-} + {H}^{+} \to {H}_{2} C {O}_{3}$

Carbonic acid is in equilibrium with $C {O}_{2}$ and ${H}_{2} O$.