The vapour pressure of a solvent decreases by $10 \ mm$ of $Hg$ when a non-volatile solute is added to the solvent. The mole fraction of the solute in the solution is $0.2$. What should be the mole fraction of the solvent if the decrease in the vapour pressure is to be $20 \ mm$ of $Hg$?

Select the correct option using $T$ (True) or $F$ (False) for the following statements: $(1)$ The decrease in vapour pressure is equal to the mole fraction of the solute. $(2)$ The relative lowering of vapour pressure is directly proportional to the amount of solute. $(3)$ The relative lowering of vapour pressure is equal to the mole fraction of the solute. $(4)$ The vapour pressure of the solution is equal to the mole fraction of the solvent.

Toluene in the vapour phase is in equilibrium with a solution of benzene and toluene having mole fraction of toluene $0.50$. If vapour pressure of pure benzene is $119 \ torr$ and that of toluene is $37.0 \ torr$ at the same temperature,mole fraction of toluene in vapour phase will be:

Relative lowering in vapour pressure of a solution containing a non-volatile solute is the ratio of:

Among the following substances,the lowest vapour pressure is exerted by

$X$ is a non-volatile solute and $Y$ is a volatile solvent. The following vapour pressures are observed by dissolving $X$ in $Y$ at different concentrations:
| $X / \text{mol L}^{-1}$ | $Y / \text{mm of Hg}$ |
| :--- | :--- |
| $0.10$ | $p_1$ |
| $0.25$ | $p_2$ |
| $0.01$ | $p_3$ |
The correct order of vapour pressures is: