Vapour pressures of benzene and toluene in a mixute at 50^(@)C are given in mm by P=179 X_(B)+92 where X_(B) is the mole fraction of benzene. Calculate. (c) If the vapours are removed and condensed into liquid and again brought to the temperature of 50^(@)C, what would be the mole fraction of benzene in the vapour phase?

Vapour pressures of benzene and toluene in a mixute at 50^(@)C are giv

1.	Vapour pressures of benzene and toluene in a mixute at 50^(@)C are given in mm by P=179 X_(B)+92 where X_(B) is the mole fraction of benzene. Calculate. (c) If the vapours are removed and condensed into liquid and again brought to the temperature of 50^(@)C, what would be the mole fraction of benzene in the vapour phase?
Answer» SOLUTION :Mole fractions in the vapour PHASE : `y_(B)=(P_(B))/(P_("Total"))=(162.6)/(199.4)=0.82,""y_(T)=(P_(T))/(P_("Total"))=(36.8)/(199.4)=0.18` After CONDENSATION, these are the mole fractions in the liquid phase New `P_(B)=0.82xx"271 mm" = "222.2 mm,New " P_(T)=0.18xx"92 mm = 16.6 mm,"` New `P_("Total")=222.2+16.6= 238.8" mm,New " y_(B)=(222.2)/(238.8)=0.93`