$1 \mathrm{~g}$ of a solute is added to $18 \mathrm{~g}$ of water. In this aqueous solution, what is the…
$1 \mathrm{~g}$ of a solute is added to $18 \mathrm{~g}$ of water. In this aqueous solution, what is the mass per cent of the solute?
$2 \%$
$5 \%$
$1 \%$
$10 \%$
Solution
Mass $\%$ of solute $=\frac{\text { Mass of solute }}{\text { Mass of solution }} \times 100$
Mass of solute $=1 \mathrm{~g}$
Mass of solvent $=18 \mathrm{~g}$
Mass of solution $=1+18=19 \mathrm{~g}$
$\therefore$ Mass $\%$ of solute $=\frac{1}{19} \times 100$
$
=5.3=5 \%
$
Hence, the correct option is (2)