Question

A solution contains sugar dissolved in 150 g of water. If the mass of the solution is 200 g, calculate the concentration in terms of the mass by mass percentage of the solution.

• A. 10%
• B. 25%
• C. 50%
• D. 75%

Answer 1

The correct option is B 25%

Given:
Mass of solution = 200 g
Mass of solvent (water) = 150 g

To find: Concentration in terms of mass by mass.
Mass of solution = Mass of solute (sugar) + Mass of solvent (water)
Therefore,
Mass of solute (sugar) = Mass of solution - Mass of solvent (water)
Hence,
Mass of solute = 200 g - 150 g
⇒ Mass of solute = 50 g
We know that,
Concentration (mass by mass percentage) of solution $=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 100$

$=\frac{50}{200}\times 100$
$=25\%$