PLS HELP ASAP this student's experiment had an additional variable that made the conclusion unreliable. What was the additional variable, and how did it affect the experiment? Hint there are 16 tablespoons in a cup, so one tablespoon is 6.25 percent of one cup

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.