Question

An aqueous solution of $HCl$ has $2\%$ mass of $HCl$ and a density of $1.02gc{m}^{-3}$. The numerical values of mass and morality, respectively, are

• A. $0.542,0.652$
• B. $0.652,0.542$
• C. $0.559,0.652$
• D. $0.559,0.559$

Answer 1

Answer: (D)

$0.559,0.559$

Let the mass of solution be $100$ g

Therefore; Mass of $HCl=2g$

Moles of $HCl=\frac{2}{36.5}=0.055$

Volume of solution $=\frac{m}{s}=\frac{100}{102}=98.04c{m}^3$

Therefore; Molality $=\frac{MolesofHCl}{Massofsolvent}=\frac{0.055}{0.098}=0.0559$

Molality $=\frac{MolesofHCl}{Volumeofsolution}=\frac{0.055}{0.09804}=0.0559$