Question

A solution contains 100 g of urea in 400 g of water. Calculate the concentration in terms of mass by mass percentage of the solution.

• A. 20
• B. 25
• C. 10
• D. 80

Answer 1

Answer: (A)

20

Mass of solute = 100 g

Mass of solvent = 400 g

Mass of solution = 400 + 100 = 500 g

Mass % of solution $=\frac{\text{Mass of solute}\times 100}{\text{Mass of solution}}$

$=\frac{100\times 100}{500}$

$=20$%

Hence, the correct option is $\text{A}$