A solution of `Na_(2)CO_(3)` is added drop by drop to litre of a solution containing `10^(-4)` mole of `Ba^(2+)` and `10^(-5)` mole of Ag, if `K_(SP)` for `BaCO_(3)` is `8.1xx10^(-9)` and `K_(SP)` for `Ag_(2)CO_(3)is 6.9xx10^(-12)`, then which is not true ?

Options

A. No precipitate of `BaCO_(3)` will appear untill `[CO_(3)^(2-)]` reaches `8.1xx10^(-5)` mole per litre
B. A precipitate of `Ag_(2)CO_(3)` will appear when `[CO_(3)^(2-)]` reaches `6.9xx10^(-5)` mol `litre^(-1)`
C. No precipitate of `Ag_(2)CO_(3)` will appear until `[CO_(3)^(2-)]` reaches `6.9xx10^(-2)` mol per litre
D. `BaCO_(3)` will be precipitated first

Answer

B

Explanation

For precipitation of `Ag_(2)CO_(3)`,
`[CO_(3)^(2-)]= (K_(SP))/([Ag^(+)]^(2)) = (6.9xx10^(-12))/([10^(-5)]^(2))`
`=6.9xx10^(-2)`
and for precipitation of `BaCO_(3)`,
`[CO_(3)^(2-)]= (K_(SP))/([Ba^(2+)])= (8.1xx10^(-9))/(10^(-4))=8.1xx10^(-5)`