Relative lowering of vapour pressure of a dilute solution is $0.5$. What is the mole fraction of the non-volatile solute?

Which of the following aqueous solutions will show maximum vapour pressure at $300 \text{ K}$?

Vapour pressure of pure water at $298 \, K$ is $23.8 \, mm \, Hg$. $50 \, g$ of urea $(NH_2CONH_2)$ is dissolved in $850 \, g$ of water. Calculate the vapour pressure of water for this solution and its relative lowering.

At $50^{\circ} C$, the vapour pressure of pure benzene is $268 \ torr$. The number of moles of non-volatile solute per mole of benzene required to prepare a solution having a vapour pressure of $167 \ torr$ at the same temperature is (molar mass of benzene $= 78 \ g \ mol^{-1}$)

The total vapour pressure of a solution of liquid $A$ and liquid $B$ is $600 \ torr$. The mole fraction of component $A$ in the liquid phase is $0.7$. If the mole fraction of $A$ in the vapour phase is $0.35$,what are the vapour pressures of pure $A$ and pure $B$ respectively?

$A$ liquid is kept in a closed vessel. If a glass plate (negligible mass) with a small hole is kept on top of the liquid surface,then the vapour pressure of the liquid in the vessel is