Question

$3$ grams of salt of molecular weight $30$ is dissolved in $250$ g of water. Find the molality of the solution.(Multiply the answer by 10).

Answer 1

$3$ g of a salt of molecular weight $30$ is dissolved in $250$ g of water. The expression for the molarity of the solution is
$Molality\left(m\right)=\frac{\text{mass of salt}}{\text{molar mass of salt}}\times \frac{1}{\text{mass of water}}$
Substituting values in the above expression, we get
$m=\frac{3}{30}\times \frac{1}{250}\times 1000=0.4$
The molality of the solution is $0.4$.