Question

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

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

Answer 1

The correct option is D $\frac{1}{76}$

373 K is the boiling point of $H_{2}O$ so $P^{\circ }=760$ mm of Hg
$\frac{P^{\circ }-P^s}{P^{\circ }}=X_{solute}$
$X_{solute}=\frac{760-750}{760}=\frac{1}{76}$