Use either raoult's law or henry's law to solve the following problems: i. a gas containing i mole% ethane is in contact with water at 20°c and 20 atm. estimate the mole fraction of dissolved ethane. 2. an equimolar liquid mixture of benzene (b) and toluene (t) is in equilibrium with its vapour at 30 °c. what is the system pressure and the composition of the vapour?