The complex compound that gives a precipitate with BaCl₂  solution is

$\begin{array}{l}\mathrm{Both}{\mathrm{CO}}_3^{-2}\mathrm{and}{\mathrm{SO}}_4^{-2}\mathrm{give}\mathrm{a}\mathrm{white}\mathrm{ppt}\mathrm{with}{\mathrm{BaCl}}_2\\ \mathrm{Solution}.{\mathrm{SO}}_4^{-2}+{\mathrm{Ba}}^{+2}\to {\mathrm{BaSO}}_4\left(\mathrm{s}\right)\downarrow \\ {\mathrm{CO}}_3^{-2}+{\mathrm{Ba}}^{+2}\to {\mathrm{BaCO}}_3\left(\mathrm{s}\right)\downarrow \\ \mathrm{The}\mathrm{complex},\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{Br}\right]{\mathrm{SO}}_4\mathrm{ionizes}\mathrm{to}{\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{Br}\right]}^{+2}\mathrm{and}{\mathrm{SO}}_4^{-2}\\ \mathrm{Thus}\mathrm{it}\mathrm{gives}\mathrm{white}\mathrm{ppt}\mathrm{with}{\mathrm{BaCl}}_2\mathrm{Solution}.\end{array}$