# How do you identify conjugate acid base pairs?

May 11, 2014

Let us take the example of Bicarbonate being placed in water to create Carbonic Acid and Hydronium ions.

$H C {O}_{3}^{-} + {H}_{2} O \to {H}_{2} C {O}_{3} + O {H}^{-}$
$B a s e + A c i d \to C o n j A + C o n j B$

On the reactant side of the equation the water (${H}_{2} O$) is the Acid as it is the hydrogen ion donor to the bicarbonate ($H C {O}_{3}^{-}$) which is the Base as it receives the hydrogen ion..

On the product side the Carbonic Acid (${H}_{2} C {O}_{3}$) is the Conjugate Acid as it is the hydrogen donor to the Conjugate Base ($O {H}^{-}$) as it receives the hydrogen ion.

$H C {O}_{3}^{-} \to {H}_{2} C {O}_{3}$
$B a s e \to C o n j A$
The Carbonic Acid (${H}_{2} C {O}_{3}$) is the Conjugate Acid pair to the Base bicarbonate ($H C {O}_{3}^{-}$) .

${H}_{2} O \to O {H}^{-}$
$A c i d \to C o n j B$

The Hydroxide ($O {H}^{-}$) is the Conjugate Base pair to the Water (H_2O#).