Calculate vapour pressure of pure volatile liquid $B$ at given temperature if mole faction of liquid $B$ and vapour pressure of pure volatile liquid $A$ are 0.4 and 400 mm Hg respectively.

$$ \left[\mathrm{P}_{\text {total }}=600 \mathrm{~mm} \mathrm{Hg}\right] $$

Calculate the molality of nonvolatile solution if solution freezes at $-0.95^{\circ} \mathrm{C}$

$\left[K_f\right.$ for water, $=1.86 \mathrm{~K} \mathrm{~mol}^{-1}$, freezing point of water $=0^{\circ} \mathrm{C}$ ]

Which of the following solutions exhibits highest freezing point depression?

Calculate the concentration of dissolved gas in water at $25^{\circ} \mathrm{C}$ if partial pressure of gas at same temperature is 0.15 atm .

$$ \left[\mathrm{K}_{\mathrm{H}}=0.15 \mathrm{~mol} \mathrm{dm}^{-3} \mathrm{~atm}^{-1}\right] $$