Calculate the mole fraction of solute in a solution if the vapour pressure of the solution and the pure solvent are $27 \text{ mm Hg}$ and $30 \text{ mm Hg}$ respectively at $298 \text{ K}$.

At $298 \ K$,vapour pressures of two pure liquids $A$ and $B$ are $200 \ mm \ Hg$ and $400 \ mm \ Hg$ respectively. If mole fractions of $A$ and $B$ in solution are $0.7$ and $0.3$ respectively,what is the mole fraction of $B$ in vapour phase?

$18 \ g$ of glucose is dissolved in $90 \ g$ of water. The relative lowering of vapour pressure of the solution is equal to

What is the mass in $g$ of a non-volatile solute with a molecular weight of $40$ that should be dissolved in $57 \ g$ of octane to reduce its vapour pressure to $80 \%$ of its original value?

The vapour pressure of $30 \%$ $(w/v)$ aqueous solution of glucose is $...... \ mm \ Hg$ at $25^{\circ} \ C$. [Given : The density of $30 \%$ $(w/v)$ aqueous solution of glucose is $1.2 \ g \ cm^{-3}$ and vapour pressure of pure water is $24 \ mm \ Hg$.] (Molar mass of glucose is $180 \ g \ mol^{-1}$.)

Explain how the solubility of a gaseous solute and the vapour pressure of a liquid solution follow Henry's and Raoult's laws.