How many gram of `CaC_(2)O_(4)` will dissolve in distilled water to make one litre of saturated solution ? `(K_(sp) =2.5xx10^(-9)` and its molecular mass is 128 )

Options

A. 0.0640 g
B. 0.0064 g
C. 0.0128 g
D. 0.0032 g

Answer

B

Explanation

`K_(sp)(CaC_2O_4)=2.5xx10^(-9)`
`K_(sp)=s^2 =2.5xx10^(-9)`
`therefore s=5xx10^(-5)`
Solubility of `CaC_2O_4 =5xx10^(-5) "mol L"^(-1)`
`=5xx10^(-5) xx128 g L^(-1)`
`=6.40xx10^(-3)` or =0.0064 g `L^(-1)`