These two substances are not the same. They are both green and they are both soluble in water. One substance has a melting point of 115 C, is soluble in alcohol, and has density of 1.88 g/cm 3 . The other substance breaks apart at 560 C, is not soluble in alcohol, and has density of 3.60 g/Cm 3. They have different properties. How could the explanation be improved?

)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.