What is the molarity of solution containing $3 \cdot 2 \mathrm{~g}$ of NaOH (Molar mass $40 \mathrm{~g}…
What is the molarity of solution containing $3 \cdot 2 \mathrm{~g}$ of NaOH (Molar mass $40 \mathrm{~g} \mathrm{~mol}^{-1}$. In $250 \mathrm{~cm}^{3}$ of water?
$0.512 \mathrm{~mol} \mathrm{dm}^{-3}$
$0.32 \mathrm{~mol} \mathrm{dm}^{-3}$
$0.032 \mathrm{~mol} \mathrm{dm}^{-3}$
$0.02 \mathrm{~mol} \mathrm{dm}^{-3}$
Solution
Mass of NaOH (m) = 3.2 g
The volume of water (V) = 250 cm3 = 0.25 L
Mol. wt of NaOH (m) = 40 g/mol
n = 3.2 / 40 = 0.08
Molarity = 0.08/0.25 = 0.32 mol dm-3