1.(a) Determine the mole fraction of methane, xi, dissolved in a light oil at 200K and 20 bar. Henry's law is valid for the liquid phase, and the gas phase may be assumed to be an ideal solution. At these conditions, Henry's law constant for methane in oil =200 bar, fugacity coefficient of pure methane gas =0.90 and mole fraction of methane in the gas phase, y1= 0.95. (b) An equimolar mixture of benzene and toluene is contained in a piston/cylinder arrangement at a temperature T. What is the maximum pressure below which the mixture exists as a vapour phase alone? At the given T, the vapour pressures of benzene and toluene are 203.9kPa and 85.3kPa, respectively. Assume that Raoult's law is valid. (c) Two substances A and B are known to form ideal liquid solutions. A vapour mixture containing 50%(mol)A and 50%(mol)B is at 311K and 101.3kPa. This mixture is compressed isothermally until condensation occurs. At what pressure does condensation occur and what is the composition of the liquid that forms? The vapour pressures of A and B are 142 kPa and 122kPa respectively