At a given temperature,the vapour pressure of pure water is $25 \ mm$ and the vapour pressure of a dilute solution of urea is $24.5 \ mm$. The molality of the solution is:

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:

$A$ solution is prepared by dissolving $10 \ g$ of a non-volatile solute (molar mass,'$M$ $g \ mol^{-1}$') in $360 \ g$ of water. What is the molar mass in $g \ mol^{-1}$ of solute if the relative lowering of vapour pressure of solution is $5 \times 10^{-3}$?

If $P^o$ and $P$ are the vapour pressure of a solvent and its solution respectively and $N_1$ and $N_2$ are the mole fractions of the solvent and solute respectively,then the correct relation is:

The vapor pressures of two liquids $A$ and $B$ are $80 \ mm$ and $60 \ mm$ respectively. If $3 \ mol$ of $A$ and $2 \ mol$ of $B$ are mixed,the total vapor pressure of the resulting solution will be .......... $mm$.

At a certain temperature,the mole fraction of a solute is $0.15$ and the vapor pressure of the pure solvent is $120 \, torr$. If the solute is non-volatile,what will be the relative lowering in vapor pressure?