A solution consists of 3.88 g benzene,C6H6 , and 2.45 g toluene ,C6H5CH3. The vapor pressure of pure benzene at 20. °C is 75 mm Hg and that of toluene at 20.0 °C is 22 mm Hg. Assume that Raoult's law holds for each component of the solution, calculate the mole fraction of benzene in the vapor. ( molar mass of benzene= 78.0 g/mole and toluene = 92.0 g/mole.)