Question

What will be the molality of the solution containing 18.25 g of $HCl$ gas in 500 g of water?

• A. 0.1 m
• B. 1 m
• C. 0.5 m
• D. 2 m

Answer 1

The correct option is B 1 m

Molality can be defined as the "number of moles" of solute per kilogram quantity of a solvent. In other words, it is the concentration of the solute in a solution.

We also know that, the molecular weight of HCl is (1 + 35.5) = 36.5

So, the "number of moles" of solute $=\frac{18.25}{36.5}=0.5mol$

$Molality=\frac{Numberofmolesofsolute}{Massofthesolvent}\times 1000$

$Molality=\frac{0.5}{500}\times 1000=1m.$

The molality of the solution is 1 m.

The correct option is B.