The solubility of `CaCO_(3)` is `7mg//L`. Calculate the `K_(sp)` of `BaCO_(3)` whne `Na_(2)CO_(3)` is added slowely a solution containing equimolar concentration of `Ca^(2+)` and `Ba^(2+)` and no precipitate is formed until `90%` of `Ba^(2+)` has beem precipitated as `BaCO_(3)`.
