Only solve for part a. How to find deltaG(400.15) in order to get k

Ethanol is produced from ethylene via the ideal gas-phase reaction at 127C and 2 bar: C2H4(g)+H2O(g) C2H6O(g). After ethanol is produced, it is stored in a vessel containing chloroform and more ethanol at 55C. At this temperature both species can exist as vapors and liquids, reaching a vapor-liquid equilibrium state at 55C. The excess Gibbs energy for this now non-ideal chloroform (1)/ ethanol(2) system is well represented by the 2-parameter Margules equation: RTGE=(1.42x1+0.59x2)x1x2 a. Find the equilibrium constant of the ideal gas-phase reaction at 127C and 2 bar. b. Find the equilibrium mole fraction of ethanol gas produced by the reaction. c. Find the pressure of the chloroform(1)/ethanol(2) system for a chloroform liquid mole fraction of 0.75. Answers: a. k=0.263