Question

Define $pH$. Find the $pH$ of $0.05MBa(OH{)}_2$ aqueous solution.

Answer 1

The pH of a solution is defined as the negative logarithm, to the base 10, of the molar concentration of $H^{+}$ ions in solution.
$pH=-lo{g}_{10}\left[H^{+}\right]$
$\left[Ba\right(OH{)}_2]=0.05M$
$\left[O{H}^{-}\right]=2\times \left[Ba\right(OH{)}_2]=2\times 0.05M=0.10M$
$pOH=-lo{g}_{10}\left[O{H}^{-}\right]=-lo{g}_{10}=0.10=1$
$pH=14-pOH=14-1=13$