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A solution cotaning `0.10 M` in `Ba(NO_(3))_(2)` and `0.10 M` in `Sr(NO_(3))_(2)`. If solid `Na_(2)CrO_(4)` is added to the solution, what is `[Ba^(2+)]`, when `SrCrO_(4)` beings to precipitate? `[K_(sp)(BaCrO_(4)) = 1.2 xx 10^(-10), K_(sp) (SrCrO_(4)) = 3.5 xx 10^(-5)]`A. `7.4 xx 10^(-7)`B. `2.0 xx 10^(-7)`C. `6.1 xx 10^(-7)`D. `3.4 xx 10^(-7)` |
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Answer» Correct Answer - D `K_(sp)(SrCrO_(4)) = [Sr^(2+)][CrO_(4)^(2-)]` `[CrO_(4)^(2-)] = (3.5 xx 10^(-5))/(0.1) = 3.5 xx 10^(-4)` `K_(sp)(BaCrO_(4)) = [Ba^(2)][CrO_(4)^(2-)]` `[CrO_(4)^(2-)]_("total") = [CrO_(4)^(2-)]` from `SrCrO_(4)` `[Ba^(2+)] = (1.2 xx 10^(-10))/(3.5 xx 10^(-4)) = 3.4 xx 10^(-7)` |
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