At 298 K, the p^H of mixture containing 1000 ml of 0.1 M H₂SO₄ and 500 ml of 1.2 M NH₄OH is (p^k_b of NH₄OH = 4.77)

$\begin{array}{l}{\mathrm{V}}_{\mathrm{a}}{\mathrm{N}}_{\mathrm{a}}=1000\left(0.1\right)2=200\mathrm{meq}\\ {\mathrm{V}}_{\mathrm{b}}{\mathrm{N}}_{\mathrm{b}}=500\left(1.2\right)=600\mathrm{meq}\\ \underset{ }{\mathrm{SA} + \mathrm{WB} } \to \mathrm{salt} + \mathrm{water}\\ 200 \mathrm{meq} 200 \mathrm{meq} 200 \mathrm{meq}\\ \mathrm{Left} \mathrm{over} \mathrm{WB}= \left(600-200\right) \mathrm{meq} =400 \mathrm{meq} ;\end{array}$

This mixture contains WB and its salt of strong acid.

This mixture acts like a basic buffer.

$\begin{array}{l}\therefore {\mathrm{p}}^{\mathrm{OH}}={\mathrm{p}}^{{\mathrm{K}}_{\mathrm{b}}}+\log \frac{{\mathrm{V}}_{\mathrm{S}}{\mathrm{N}}_{\mathrm{S}}}{{\mathrm{V}}_{\mathrm{a}}{\mathrm{N}}_{\mathrm{a}}}\\ {\mathrm{p}}^{\mathrm{OH}}=4.77+\log \frac{200}{400}\\ {\mathrm{p}}^{\mathrm{OH}}=4.77-0.301\\ {\mathrm{p}}^{\mathrm{H}}=14-4.77+0.301\\ {\mathrm{p}}^{\mathrm{H}}=9.531\end{array}$