Liquid methyl ethyl ketone (MEK) is introduced into a vessel containing air. The system temperature is increased to 50.0C, and the vessel contents reach equilibrium with some MEK remaining in the liquid state. The equilibrium pressure is 1600.0 mm Hg. Physical Property Tables Vapor Mole Fraction Mixtures of MEK vapor and air that contain between 1.80 mole% MEK and 11.5 mole% MEK can ignite and burn explosively if exposed to a flame or spark. What is the mole fraction of MEK in the vessel