Aqueous solutions of `Na_(2)C_(2)O_(4)` and `CaCI_(2)` are mixed and precipitate of `CaC_(2)O_(4)` formed is filered and dried. `250 mL` of the saturated solution of `CaC_(2)O_(4)` required `6.0 mL` of `0.001M KMnO_(4)` solution in acidic medium for complete titration.
`K_(sp)` of `CaC_(2)O_(4)` is

Options

A. `2.25xx10^(-12)`
B. `2.25xx10^(-10)`
C. `3.6xx10^(-9)`
D. `4.0xx10^(-9)`

Answer

C

Explanation

Moles of `C_(2)O_(4)^(2-) rarr 1.5 xx 10^(-5) (250 mL)^(-1)`
`[C_(2)O_(4)^(2-)] = [Ca^(2+)] = (1.5 xx 10^(-5)xx1000mL)/(250mL) = 6 xx 10^(-5)M`
`K_(sp) = [Ca^(2+)] [C_(2)O_(4)^(2-)] = (6 xx 10^(-5))^(2) = 3.6 xx 10^(-9)M^(2)`