100 ml of 0.2 ${\mathrm{MH}}_2{\mathrm{SO}}_4$ solution is mixed with 400ml of0.05 M ${\mathrm{Ba}}_3{\left({\mathrm{PO}}_4\right)}_2$. Calculate the concentration of $\left[{\mathrm{Ba}}^{+2}\right]$ ion in resulting solution.

$$\begin{gathered} 3{\mathrm{H}}_2{\mathrm{SO}}_{4 }+{ \mathrm{Ba}}_3{\left({\mathrm{PO}}_4\right)}_2⟶3{\mathrm{BaSO}}_4\left(s\right)\downarrow +2{\mathrm{H}}_3{\mathrm{PO}}_4 \\ 20 20 \end{gathered}$$

( LR)                                           $\frac{\left(20-\frac{20}{3}\right)\times 3}{500}=0.08$

$\begin{array}{l}\left[{\mathrm{Ba}}_3{\left({\mathrm{PO}}_4\right)}_2\right]=\frac{13.33}{500}=0.0266\\ \left[{\mathrm{Ba}}^{2+}\right]=3\left[{\mathrm{Ba}}_3{\left({\mathrm{PO}}_4\right)}_2\right]=0.08\mathrm{M}\end{array}$