The complex compound that gives a precipitate with BaCl2 solution is
CoNH35SO4Br
CoNH35BrSO4
CoNH35BrNO32
CoNH35SO4Cl
Both CO3−2 and SO4−2 give a white ppt with BaCl2SO4−2+Ba +2→BaSO4s↓CO3−2+Ba+2→BaCO3s↓The complex,CONH35BrSO4 ionizes to CONH35Br+2 and SO4−2Thus it gives white ppt with BaCl2 Solution.