The vapour pressure of solvent is 20 torr, while that of its dilute solution is 17 torr, the mole fraction of the solvent is

Question

The vapour pressure of solvent is 20 torr, while that of its dilute solution is 17 torr, the mole fraction of the solvent is (A) 0.6 (B) 0.85 (C) 0.5 (D) 0.7

Tardigrade Admin · Accepted Answer

From question P°=20 torr, PS=17 torr ∴ (Po-Ps/Po)=X textsolute (3/20)=X textsolute or =X textsolute=0.15 X textsolvent=0.4

Q. The vapour pressure of solvent is 20 torr, while that of its dilute solution is 17 torr, the mole fraction of the solvent is

$0.6$

$0.85$

$0.5$

$0.7$

From question
$P^{\circ} = 20$ torr, $PS = 17$ torr
$∴ \frac{P ^{o} - P _{s}}{P ^{o}} = X_{solute}$
$\frac{3}{20} = X_{solute}$
or $= X_{solute} = 0.15$
$X_{solvent} = 0.4$