Question

3 g of salt having molecular weight 30 is dissolved in 250 g of water. The molality of the solution is:

• A. $0.4$
• B. $0.2$
• C. $0.6$
• D. $0.8$

Answer 1

The correct option is A $0.4$

$Molality=\frac{\text{moles of solute}}{\text{mass of solvent (in Kg)}}$

$\Rightarrow \text{moles of solute}=\frac{3}{30}=\frac{1}{10}$

$Molality=\frac{1}{10}\times \frac{1000}{250}$

$\Rightarrow 0.4m$