Question

Vapour pressure of water at the room temperature is 30 mm Hg. If the mole-fraction of the solvent in the aqueous solution of a non-volatile solute is 0.9, then the vapour pressure of the solution would be:

• A. $30$ mm Hg
• B. $33.3$ mm Hg
• C. $27$ mm Hg
• D. $29.1$ mm Hg

Answer 1

The correct option is C $27$ mm Hg

Given that,

$X_{solute}=0.9$

$P_{H_{2}O}^o=30mmHg$

$\Delta P=X_{solute}\times P_{H_{2}O}^o$

$=0.9\times 30mmHg$

$=27mmHg$

So, the correct option is $C$