Three solutions of strong electrolytes 25 mL of 0.l M HX, 25 mL of $0.1{\mathrm{MH}}_{2}Y$and 50 mL of $0.1\mathrm{NZ}{\left(\mathrm{OH}\right)}_2$ are mixed. What is the pOH of the solution?

[Given log 5 = 0.7]

There are total three solutions of strong electrolytes are given.

These solutions in 25 mL of 0.l M HX, 25 mL of $0.1{\mathrm{MH}}_{2}Y$and 50 mL of $0.1\mathrm{NZ}{\left(\mathrm{OH}\right)}_2$ are mixed. 

The pOH value for this mixture of solution,

$\begin{array}{l}\mathrm{pH}=-{\log }_{10}\left[\frac{25\times 0.1+25\times 0.1\times 2-50\times 0.1}{100}\right]\\ \therefore \mathrm{pOH}=14-1.6=12.4\end{array}$