Exercise 5.2
Your mother gives you a bottle of orange juice concentrate to mix with water and serve it to your visiting friends. She asks you to mix two tablespoons of the concentrate with water in a glass tumbler. If each tablespoon measures mL and you make mL of juice per person, what is the % v/v of orange juice concentrate in the mixture you prepared?
NCERT’s answer
$\displaystyle 20$ % v/v
The concentrate is $\displaystyle 20$ % v/v in the juice you prepared.
Volume of concentrate (solute) \(\displaystyle = 2 \times 15\ \text{mL} = 30\ \text{mL} \)
Volume of juice (solution) \(\displaystyle = 150\ \text{mL} \)
\(\displaystyle \text{Volume by volume percentage} = \dfrac{\text{Volume of solute}}{\text{Volume of solution}} \times 100 \)
\(\displaystyle = \dfrac{30\ \text{mL}}{150\ \text{mL}} \times 100 = 20\ \%\ v/v \)