Question

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

Answer 1

Correct Answer - C
`underset(Conc.: )(BASO_(4))hArrunderset(1xx10^(-4))(Ba^(2+))+underset(s)(SO_(4)^(2-))`
`K_(sp)=4xx10^(-10)`
`4xx10^(10)=1xx10^(-4)xxs`
`(s=4xx10^(-10))/(1xx10^(-4))=4xx10^(-6)M`