Question

Methanol and ethanol form a nearly ideal solution at 300K. A solution is made by mixing 32 g of methanol and 23 g of ethanol at 300 K. Calculate the partial pressures of constituents and the total pressure of the solution. (At 300K, P°CH3OH = 90 mm Hg, P°C2H5OH = 51 mm Hg)

The vapour pressures of benzene and toluene at 20°C are 75 mm and 22 mm Hg respectively. 22.4 g of benzene and 64.4 g of toluene are mixed. If the two form an ideal solution, calculate the mole fraction of benzene in vapour phase when vapours are in equilibrium with the liquid phase.

At 25°C, the vapour pressure of water is 22.75 mm Hg. Calculate the vapour pressure at the same temperature of 5% aqueous solution of urea (NH2CONH2).

Solutions of two volatile liquids A and B obey Raoult's law. At a certain temperature, it is found that when the total pressure above a given solution is 400 mm Hg, the mole fraction of A in the vapour is 0.45 and in the liquid is 0.65. What are the vapour pressures of the two liquids in the pure state at the given temperature?