The solution formed a precipitate when HBr is added. This indicates that the cation present would be silver ion(Ag\(^{+}\)) as silver forms an insoluble precipitate with bromide ion.
The equation representing the formation of silver bromide precipitate is:
\(Ag^{+}(aq)+HBr(aq)-->AgBr(s)+H^{+}(aq)\)
Bromides of all the other cations,\(Cu^{2+},Ag^{+},Ba^{2+},Mn^{2+}\)are soluble in aqueous solutions.
After removing the precipitate of AgBr by filtration, the supernatant solution is treated with \(H_{2}SO_{4}\)and another precipitate forms. This would be due to the presence of \(Ba^{2+}\)ions as barium sulfate is an insoluble precipitate.
The equation representing the formation of barium sulfate precipitate is:
\(Ba^{2+}(aq)+H_{2}SO_{4}(aq)-->BaSO_{4}(s)+2H^{+}(aq)\)
