# Question f0437

Apr 29, 2015

In one word: yes.

If you know the concentration of the hydroxide ions, you can determine the solution's pOH by

$p O H = - \log \left(\left[O {H}^{-}\right]\right)$

$p O H = - \log \left(1.9 \cdot {10}^{- 6}\right) = 5.72$

This will indirectly get you the pH of the solution

$p {H}_{\text{sol}} = 14 - p O H = 14 - 5.72 = 8.28$

Now use the pH to determine the concentration of the hydronium ions

[H_3O^(+)] = 10^(-pH_"sol") = 10^(-8.28) = 5.3 * 10^(-9)"M"#

Alternatively, you can calculate the concentration of the hydronium ions directly by

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

$\left[{H}_{3} {O}^{+}\right] = {10}^{- 14} / \left(1.9 \cdot {10}^{- 6}\right) = 0.53 \cdot {10}^{- 8} = 5.3 \cdot {10}^{- 9} \text{M}$

Here's a diagram that shows how pH, pOH, $\left[{H}_{3} {O}^{+}\right]$, and $\left[O {H}^{-}\right]$ relate to each other