Question

$10\, g$ of $NaOH$ is dissolved in $500\, ml$ of aqueous solution. Calculate the molarity of this solution? (Formula weight of $NaOH=40$)

• A. $0.5 \times 10^{-3} M$
• B. $0.4\, M$
• C. $0.25 \times 10^{-3} M$
• D. $0.5\, M$

Answer 1

Answer: (D)

$\therefore $ Molarity $=\frac{\text { Mass of solute }\left(\text { in } g L^{-1}\right)}{\text { Molar of solute }\left(\text { in } g mol^{-1}\right)}$
$=\frac{\frac{10}{500} \times 1000}{40} M=0.5\, M$