Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.
Calculate (a) molality (b) molarity and (c) mole fraction of KI if the density of 20% (mass/mass) aqueous KI is 1.202 g mL-1.
Vapoure pressure of pure water (solvent) at 298 K, p0 = 23.8 mm
Vapour pressure of solution, p = ?
Mass of solvent ,W = 850 g
Mass of solute,M = 50 g
Mol. mass of water (H2O), M = 18 g mol–1
Mol.mass of urea NH2 CO NH2
= 14 + 2 + 12 + 16 + 14 + 2
= 60 g mol–1
According to Raoult's law,
Hence, 23.78 mm Hg. Ans.