What is minimum concentration of `SO_(4)^(2-)` required to precipitate `BaSO_(4)` in solution containing `1 xx 10^(-4)` mole of `Ba^(2+)` ? (`K_(sp)` of `BaSO_(4) = 4 xx 10^(-10)`)

Options

A. ` 4 xx10^(-10)` M
B. ` 2 xx 10^(-7)`M
C. ` 4 xx 10^(-6)` M
D. ` 2 xx 10^(-3)` M

Answer

C

Explanation

`BaSO_(4) hArr Ba^(2+) +SO_(4)^(2-)`
`K_(sp) = S^(2) rArr S = sqrt(K_(sp)), K_(sp) = [ Ba^(2+)] xx [SO_(4)^(2-)] `
` 4 xx 10^(-10) = [ 1 xx 10^(-4)] xx [ SO_(4)^(2-)] `
`[SO_(4)^(2-)] = (4xx10^(-10))/(1xx10^(-4)) = 4 xx 10^(-6)`