6.5 g of Aspirin is dissolved in 450 g of water. The mass percentage of the resultant solution is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 1.423 %
The mass percentage of a component is its mass as a percentage of the total mass of the solution (solute + solvent):
\( \displaystyle \text{Mass }\%=\frac{\text{mass of solute}}{\text{mass of solution}}\times100 \)
Here the solute is aspirin (6.5 g) and the solvent is water (450 g).
\( \displaystyle \text{Mass of solution}=6.5+450=456.5\ \mathrm{g} \)
\( \displaystyle \text{Mass }\%=\frac{6.5}{456.5}\times100 \)
\( \displaystyle \text{Mass }\%=1.4239\approx1.42\,\% \)
So the mass percentage of aspirin is about 1.42%, which matches Option (3), 1.423 %. Dividing by the mass of the solvent (450 g) instead of the solution would give 1.444 %, the value in Option (4).
NCERT (2026-27 edition):
Expressing Concentration of Solutions – “… (i) Mass percentage (w/w): The mass percentage of a component of a solution is defined as:
Mass % of a component = (Mass of the component in the solution / Total mass of the solution) × 100 (1.1)”