In a real column, the mole fraction of methanol in vapor exiting stage 1 is 0.675 and the liquid exiting stage 4 is 0.325. The concentrations match methanol concentration in the vapor and liquid streams exiting the ideal stage in Question 6.. Indicate which among the following statements are correct: A. The average stage efficiency is 25% B. The phases leaving a stage in a real column are at equilibrium. C. Due to inadequate contacting, the phases exiting a stage in a real column are not at equilibrium. Stated differenty, only a fraction of the potential transport of methanol and water between the phases occurred. D. Stage efficiency is always 25% A and C A and B D If the stage efficiency of the column is increased substantially, the impact will be (pick all the correct statements) A. Methanol mole fraction in the vapor > 0.675 B. Methanol mole fraction in the liquid > 0.325 C. Methanol mole fraction in the liquid