Question

A solution contains 30 g of salt mixed in 90 g of water. What is the concentration of the solution in terms of mass by mass percentage?

• A. 25%
• B. 50%
• C. 33.33%
• D. 75%

Answer 1

The correct option is A 25%

Mass by mass percentage for the concentration of a solution is given by:
$\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 100$
$\Rightarrow \frac{\text{M}assofsolute}{\text{Mass of solute + Mass of solvent}}\times 100$
$\Rightarrow \frac{30g}{30g+90g}\times 100$
$\Rightarrow \frac{30g}{120g}\times 100$
$\Rightarrow \frac{1}{4}\times 100$
$\Rightarrow \text{25\%}$