Question

The density of NaOH solution is 1.2 g cm–3 . The molality of this solution is ...... m.
(Round off to the Nearest Integer)
[Use : Atomic masses : Na : 23.0 u O : 16.0 u H : 1.0 u Density of H2O : 1.0 g cm–3]

Answer 1

Volume of the solution = x
Mass of solute = 0.2 x gram
Mass of water = x gram
Atomic mass of NaOH= 40
Molarity = $\frac{\text{moles of solute}}{\text{liters of solution}}$
Substituting the value =$\frac{0.2x \times1000}{40x}$
$= \frac{200}{4}$
= 5m
So, the correct answer is 5m.