Chemistry - Ionic Equilibrium Question with Solution | TestHub

Milli equivalents of$\mathrm{HCl}\left({\mathrm{N}}_{\mathrm{a}}{\mathrm{V}}_{\mathrm{a}}\right)=50\times 1=50$
Milli equivalents of$\mathrm{NaOH}\left({\mathrm{N}}_{\mathrm{b}}{\mathrm{V}}_{\mathrm{b}}\right)=30\times 1=30$
Since${\mathrm{N}}_{\mathrm{a}}{\mathrm{V}}_{\mathrm{a}}>{\mathrm{N}}_{\mathrm{b}}{\mathrm{V}}_{\mathrm{b}}$
$\left[{\mathrm{H}}^{+}\right]=\frac{{\mathrm{N}}_{\mathrm{a}}{\mathrm{V}}_{\mathrm{a}}-{\mathrm{N}}_{\mathrm{b}}{\mathrm{V}}_{\mathrm{b}}}{{\mathrm{V}}_{\mathrm{a}}+{\mathrm{V}}_{\mathrm{b}}}=\frac{50-30}{80}=\frac{20}{80}=0.25=2.5\times {10}^{-1}$
$\mathrm{pH}=-\log \left[{\mathrm{H}}^{+}\right]=-\log \left(2.5\times {10}^{-1}\right)=1-0.3979=0.6021$
$\mathrm{pH}\times {10}^4=0.6021\times {10}^4=6021$