Question

The molality of $648g$ of pure water is:

• A. $36m$
• B. $55.5m$
• C. $3.6m$
• D. $5.55m$

Answer 1

The correct option is B $55.5m$

Molality = $\frac{\text{no of moles of solute}}{\text{mass of solvent in kg}}$

Molar mass of water = $18g$

Mass of water = $648g$

No of moles of water $=\frac{648}{18}=36mol$

Molality = $\frac{36\times 1000}{648}=55.5m$