# What is the pOH of a 8.4x10^-11 M OH^- solution?

Aug 28, 2016

$p O H = 10.08$

#### Explanation:

The $p O H$ of a solution is defined in terms of the concentration of hydroxide ions in solution as follows:

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

In this question, $\left[O {H}^{-}\right] = 8.4 \times {10}^{- 11} M$, thus the $p O H$ can be calculated by:

$p O H = - \log \left(8.4 \times {10}^{- 11}\right) = 10.0757 \cong 10.08$

Note that if the concentration is given with 2 significant figures , the $p O H$ value is written with two decimal places.