Correct Answer - A
`CaSO_(4)(s)+aq hArr Ca^(2+)(aq)+SO_(4)^(2-)(aq)`
`K_(sp)=[Ca^(2+)][SO_(4)^(2-)]`
Suppose the solubility of `CaSO_(4) = s "mol" L^(-1)`
`K_(sp)=sxxs=s^(2)`
`9.0xx10^(-6) = s^(2) or s=3xx10^(-3) "mol" L^(-1)`
Molar mass of `CaSO_(4) = 40 + 32 + 64 = 136 g "mol" ^(-1)`
`:. 1g CaSO_(4) = (1)/(136) ` mol
`3xx10^(-3)` mol of `CaSO_(4)` require minimum water to dissolve = 1 L
`:. (1)/(136) ` mol of `CaSO_(4)` will require water
`=(1)/(3xx10^(-3))xx(1)/(136) ~=2.45 L`
