Chemistry - Ionic Equilibrium Question with Solution | TestHub

Apply common ion effect total$\left[\mathrm{\text{O}}{\mathrm{\text{H}}}^{-}\right]\mathrm{\text{i}}\mathrm{\text{o}}\mathrm{\text{n}}=10^{-10}+10^{-7}$
$\mathrm{\text{p}}\mathrm{\text{O}}\mathrm{\text{H}}=-\mathrm{\text{l}}\mathrm{\text{o}}\mathrm{\text{g}}(10^{-10}+10^{-7})$$\left(\therefore {10}^{-10}<<{10}^{-7}\right)$
$\left[{\text{OH}}^{-}\right]={10}^{-7}$
$\text{pOH}\simeq 7$
$\text{pH}\simeq 7$