Question

The molecular formula of a commercial resin used for exchanging ions in water softening is $C_8{H}_{7}S{O}_{3}Na$ (Mol. wt. 206). What would be the maximum uptake of $C{a}^{2+}$ ions by the resin when expressed in mole per gram resin?

• A. $\frac{1}{103}$
• B. $\frac{1}{206}$
• C. $\frac{2}{309}$
• D. $\frac{1}{412}$

Answer 1

The correct option is D $\frac{1}{412}$

1 g of $C_8{H}_{7}S{O}_{3}Na$ = $\frac{1}{206}$ mole

$2C_8{H}_{7}S{O}_{3}Na$ + $C{a}^{2+}$ $\to$ $(C_8{H}_{7}S{O}_3{)}_{2}Ca$ + $2N{a}^{+}$

$\frac{1}{206}$ moles of $C_8{H}_{7}S{O}_{3}Na$ reacts with $\frac{1}{412}$ moles of $C{a}^{2+}$