At a pressure of 760 torr, acetic acid (CH₃COOH; boiling point = 118.1 °C) and 1,1-dibromoethane (C₂H₄Br₂; boiling point = 109.5 °C) form an azeotropic mixture, boiling at 103.7 °C, that is 25% by mass acetic acid. At the boiling point of the azeotrope (103.7 °C), the vapor pressure of pure acetic acid is 471 torr and that of pure 1,1-dibromoethane is 637 torr.

(a) Calculate the vapor pressure of each component and the total vapor pressure at 103.7 °C if the solution had obeyed Raoult’s law for both components.

(b) Compare your answer to part a with the actual vapor pressure of the azeotrope. Is the deviation of this azeotropic mixture from Raoult’s law positive or negative?

(c) Compare the attractive forces between acetic acid and dibromoethane with those in the two pure substances.