# Calculate the volume of solvent required to prepare 20 % by volume (v/v) solution by using 70 ml of $H_2SO_4$.

Volume percentage = 20
Volume of $H_2SO_4$ = 70ml
Volume of solvent = x = ?
We know, v / v% =$\large\frac{V_{solute}}{V_{solution}}$$\times 100 \Rightarrow \large\frac{20\times 70}{x+70}$$\times 100$
$\Rightarrow 20(x+70)=7000$
$\Rightarrow 20x=5600$
$x=\large\frac{5600}{20}$$=280ml$
Therefore, the volume of solvent required to prepare 20% (v/v) solution is 280 ml.
Hence (B) is the correct answer.