Calculate the molar mass of solute when 4 g of it dissolved in $1 \mathrm{dm}^3$ solvent has osmotic pressure 2 atm at 300 K . [R $\left[=0.082 \mathrm{~dm}^3 \mathrm{~atm} \mathrm{~K} \mathrm{~mol}^{-1}\right]$

Calculate $\Delta \mathrm{T}_{\mathrm{f}}$ of aqueous 0.01 m formic acid if van't Hoff factor is 1.1

$$\left[\mathrm{K}_{\mathrm{f}}=1.86 \mathrm{~K} \mathrm{~Kg} \mathrm{~mol}^{-1}\right]$$

What is the relation between the vapour pressure of solution, vapour pressure of solvent and its mole fraction in the solution?

Calculate vapour pressure of a solution containing mixture of 2 moles of volatile liquid A and 3 moles of volatile liquid $B$ at room temperature. $\left(\mathrm{P}_{\mathrm{A}}^{\circ}=420, \mathrm{P}_{\mathrm{B}}^{\circ}=610 \mathrm{~mm} \mathrm{~Hg}\right.$)