Question

$20.6NaBr$ is dissolved in $500ml$ solution what is the molarity of resulting?

• A. $0.6$
• B. $0.4$
• C. $1$
• D. None

Answer 1

The correct option is B $0.4$

$molarity=\frac{\text{moles of solute}}{\text{Litre of solvent}}$

$\text{moles of}NaBr=\frac{\text{Weight of}NaBr}{\text{Mass of}NaBr}=\frac{20.6}{102.89}=0.2$

$\text{Litre of solution}=\frac{\text{Volume of solution}}{1000}=\frac{500}{1000}=0.5$

$\therefore molality=\frac{\text{moles of solute}}{\text{Litre of solvent}}=\frac{0.2}{0.5}=0.4M$

Hence, the correct answer is 0.4.