Which solution will show the maximum vapour pressure at $300 \ K$?

When $0.25 \text{ moles}$ of a non-volatile, non-ionizable solute was dissolved in $1 \text{ mole}$ of a solvent, the vapor pressure of the solution was $x\%$ of the vapor pressure of the pure solvent. What is $x$ (in $\%$)?

The vapour pressure of a solution of methyl alcohol and ethyl alcohol is represented as $P = 115 X_A + 140$,where $X_A$ is the mole fraction of methyl alcohol. The value of $\lim_{X_A \to 0} \frac{P_B^o}{X_B}$ is

Two liquids $A$ and $B$ have vapour pressure in the ratio $P_A^o : P_B^o = 1 : 3$ at a certain temperature. If the ratio of mole fractions of $A$ to $B$ in the vapour phase is $4 : 3$,then the mole fraction of $B$ in the solution at the same temperature is

Vapour pressure of a pure solvent at $90\,^{\circ}C$ is $1020\, torr$. $A$ solution of $0.1\, m$ concentration has a vapour pressure of $1000\, torr$. What is the molecular weight of the solvent?

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