# What is an example of an aqueous base?

Sep 6, 2017

Any aqueous solution of a base qualifies......

#### Explanation:

$N a O H \left(a q\right)$, $K O H \left(a q\right)$, $N {a}_{2} C {O}_{3} \left(a q\right)$

Water undergoes the following equilibrium.....the $\text{autoprotolysis reaction}$:

$2 {H}_{2} O \left(l\right) r i g h t \le f t h a r p \infty n s {H}_{3} {O}^{+} + H {O}^{-}$

And the given equilibrium has been precisely measured under standard conditions....

$\left[{H}_{3} {O}^{+}\right] \left[H {O}^{-}\right] = {10}^{-} 14$

If $\left[H {O}^{-}\right] > {10}^{-} 7 \cdot m o l \cdot {L}^{-} 1$, then the solution is basic.......and if $\left[H {O}^{-}\right] < {10}^{-} 7 \cdot m o l \cdot {L}^{-} 1$, then the solution is acidic.....

We can introduce the $p H$ measurement by taking $- {\log}_{10}$ of both sides......$\left[{H}_{3} {O}^{+}\right] \left[H {O}^{-}\right] = {10}^{-} 14$

Thus $- {\log}_{10} \left[{H}_{3} {O}^{+}\right] - {\log}_{10} \left[H {O}^{-}\right] = {\underbrace{- {\log}_{10} \left({10}^{-} 14\right)}}_{14}$

And thus our defining relationship, which you will use shortly.....

${\underbrace{- {\log}_{10} \left[{H}_{3} {O}^{+}\right]}}_{p H} {\underbrace{- \left({\log}_{10} \left[H {O}^{-}\right]\right)}}_{p O H} = {\underbrace{- {\log}_{10} \left({10}^{-} 14\right)}}_{14}$

## p H+ p OH = 14

So actual examples.....$N a O H \left(a q\right)$, $N {a}_{2} C {O}_{3} \left(a q\right)$, $N {H}_{3} \left(a q\right)$, $K O H \left(a q\right)$, $N a F$..........