Question

The vapour pressure of a dilute aqueous solution of glucose is 750 mm of mercury at 373 K. The mole fraction of solute is:

• A. $\frac{1}{10}$
• B. $\frac{1}{7.6}$
• C. $\frac{1}{35}$
• D. $\frac{1}{76}$

Answer 1

Answer: (D)

$\frac{1}{76}$

According to Raoult's Law,

$\frac{△P}{P}=X_{Solute}$

The pressure value at $373K=760mm$

$\Rightarrow \frac{760-750}{760}=X_{Solute}$

$\Rightarrow$ mole fraction of solute $=\frac{1}{76}$

Hence, the correct option is $D$