Question

A student wants to prepare a solution of acetone and water having $30\%$ v/v. If $6mL$ of acetone has been taken then how much water must be added to get the desired concentration?

Answer 1

Volume of solute (acetone) $=6mL$
Concentration (v/v%) of solution $=30\%$

Let the volume of water (solvent) required to be x mL.
So, the volume of solution = Volume of solute + Volume of solution
= (6 + x) mL.

We know that,
Concentration of a solution (v/v%) $=\frac{Volumeofsolute}{Volumeofsolution}\times 100$


$\Rightarrow \frac{6}{6+x}\times 100=30$
$\Rightarrow 600=180+30x$
$\Rightarrow 30x=600-180$
$\Rightarrow x=\frac{420}{30}$
$x=14mL$