Q: Why is the $\ce{CO3^2-}$ anion used to precipitate Barium from $\ce{BaBr2}$ and not another anion, such as $\ce{PO4^3-}$, or $\ce{SO4^2-}$?
I am studying high school Chemistry, and the current unit is precipitations. The worked example states that $\ce{Na2CO3}$ can be used to precipitate $\ce{Ba^2+}$ from a solution of $\ce{BaBr2}$, which makes sense.
However, it does not explain why the $\ce{CO3^2-}$ anion should be selected, when according to the solubility table $\ce{SO4^2-}$ and $\ce{PO4^3-}$, would both be able to precipitate $\ce{Ba^2+}$ from $\ce{BaBr2}$. Am I missing something obvious? Why is it that the $\ce{CO3^2-}$ anion is favoured over the other two anions? `