At ?10 Degree C, the vapor pressure of ethyl bromide is 90.0 Torr and that of ethyl chloride is 302.5 Torr. Assume that the solution ?s ?deal. Assume there is only a trace of liquid present and the mole fraction of ethyl chloride in the vapor is 0.82 and answer these questions: a. What is the total pressure and the mole fraction of ethyl chloride in the liquid? b. If there are 6.50 mol of liquid and 3.80 mol of vapor present at the same pressure as in part (a), what is the overall composition of the system?