$12 \ V \ H_2O_2$ solution contains $680 \ g \ H_2O_2$. Then $\% \ W/V$ and volume of the solution is respectively ........ and ...........

(A) The strength of $H_2O_2$ in terms of $\% \ W/V$ is given by the formula: $\text{Strength} \ (\% \ W/V) = \frac{\text{Volume strength}}{5.6} = \frac{12}{5.6} \approx 2.14 \% \ W/V$.
Given mass of $H_2O_2 = 680 \ g$.
Since $\% \ W/V = \frac{\text{mass of solute in } g}{\text{volume of solution in } mL} \times 100$,we have $2.14 = \frac{680}{V} \times 100$.
$V = \frac{68000}{2.14} \approx 31775.7 \ mL \approx 31.78 \ L$.