Problem. The flash point of a liquid mixture can be estimated by finding the temperature at which the equilibrium concentration of the flammable vapors in air reaches a concentration such that yi LFL 1.0 where y; is the vapor phase mole percent of component i and LFL is the lower flammable limit concentration of component i, expressed in mole percent. Estimate the flash point of a liquid mixture containing 60 mole percent n-octane, 15 mole percent n-nonane, and 25 mole percent n- decane. The LFL values are 1.0 percent for n-octane, 0.8 percent for n-nonane, and 0.8 percent for n-decane. Vapor pressure data (Antoine equation) can be found in Appendix A of your textbook.