Question

What will be the molality of a solution of glucose in water which is $10\%w/W$ ?

• A. $0.01m$
• B. $0.617m$
• C. $0.668m$
• D. $1.623m$

Answer 1

Answer: (B)

Molality $=\frac{\text{ no of moles of solute }}{\text{ mass of solvent in }kg}$
Molar mass of glucose $=180g$
Mass of glucose $=10$
No of moles of glucose $=\frac{10}{180}=0.0556mol$
the solution of glucose in water which is $10\%w/W$ means $10g$ of glucose in $100g$ of solution
Mass of solvenyt$=100-10=90g=0.090kg$
Molality $=\frac{0.556}{0.090}=0.617m$