# What is the pOH of a solution that has OH concentration equal to 1.36×10^-10" mol"*"dm"^(-3) ?

Mar 31, 2018

$\text{pOH} = 9.866$

#### Explanation:

By definition
"pOH"=-log_(10)["OH"^-]
where $\left[{\text{OH}}^{-}\right]$ is the hydroxide ion concentration of the solution in $\text{M}$ or ${\text{mol"*"dm}}^{- 3}$, moles per cubic decimeter, or equivalently moles per liter.

Substituting ["OH"^-]=1.36*10^(-10)" mol"*"dm"^(-3),
$\text{pOH} = 9.866$.

Note that by convention the number of decimal places the $\text{pOH}$ value has shall equal to the number of significant figures in the value of $\left[{\text{OH}}^{-}\right]$. $\left[{\text{OH}}^{-}\right]$ has $3$ significant figures, which correspond to three decimal places for the $\text{pOH}$ measurement.