How much copper sulphate will be required to saturate 100g of a dilute aqueous solution of `CuSO_(4)` at `25^(@)C` if 10g of the dilute solution leave on evaporation and drying 1.2g of anhydrous `CuSO_(4)` ? The solubility of `CuSO_(4)` in water at `25^(@)C` is 25.

Explanation

100g of dilute solution of `CuSO_(4)` contain
`=1.2 xx 10 = 12.0 g CuSO_(4)`
Mass of water present in dilute solution
`=(100-12)=88g`
To saturate 100g of water, `CuSO_(4)` required = 25g
So, to saturate 88g of water, `CuSO_(4)` required `= (25)/(100)xx88`
`=22g`
Thus, the mass of `CuSO_(4)` to be added to 100g of dilute solution to saturate it `= (22-12)=10g`.