1-propanol (p*1 = 20.9 torr at 25 °C) and 2-propanol (p*2 = 45.2 torr at 25 °C) form ideal solutions in all proportions. Let x1 and x2 represent the mole fractions of 1-propanol and 2-propanol, respectively, in a liquid mixture and y1 and y2 represent the mole fractions of each in the vapor phase For a solution of these liquids with x1 = 0.510, calculate the composition of the vapor phase at 25 °C if the vapor above the liquid phase is composed only of 1-propanol and 2-propanol.