Silver ions are added to a solution with  $\left[B{r}^{-}\right]=\left[C{l}^{-}\right]=\left[C{O_3}^{-2}\right]=\left[As{O_4}^{-3}\right]=0.1M$. Which compound will precipitate with lowest $\left[A{g}^{+}\right]?$

Since here the anions are ${\mathrm{Br}}^{-},{\mathrm{Cl}}^{-},{\mathrm{CO}}_3^{2-}$and $A{s}_2{O}_3^{2-}$, So the probable precipitates will be AgBr,AgCl, Ag₂CO₃ only AgBr has lowest value of solubility product i.e. Ksp of AgBr=5×10⁻¹³. So when Ag+ ions are added to the solution, AgBr will precipitate at the lowest concentration of Ag+.