The molecular formula of a commercial resin used for exchanging ions in water softening is `C_(8)H_(7)SO_(3)Na(mol. Wt. 206)` . What would be the maximum uptake of `Ca^(2+)` ions by the resin when expressed in mole per gram resin?

Options

A. `(1)/(103)`
B. `(1)/(206)`
C. `(2)/(309)`
D. `(1)/(412)`

Answer

D

Explanation

`{:(underset("2 moles")(2C_(8)H_(7)SO_(3)^(-)Na^(+))+underset(" 1 mole")(Ca^(2+))rarr(C_(8)H_(7)SO_(3)^(-))Ca^(2+)),(=2xx206=412g" "+2Na^(+)):}`
Thus, 412 g of resin take up `Ca^(2+)` ions = 1mole
`therefore" 1 g of resin will take up "Ca^(2+) " ions"=(1)/(412)"mole"`
i.e, uptake of `Ca^(2+)` ions in mole per gram resin
`=(1)/(412)`