At 298 ~K , vapour pressures of two pure liquids A and B are 200 and 400 ~mm Hg respectively, if mole fractions of A and B in solution are 0.7 and 0.3 respectively? What is the mole fraction of B in vapour phase?

Step-by-step solution

Given, aligned p_A^ & =200 ~mm Hg p_B^ & =400 ~mm Hg aligned Mole fraction of A in solution = _A=0.7 Mole fraction of B in solution = _B=0.3 aligned p_ Total & = _A p_A^ + _B p_B^ & =(0.7 200)+(0.3 400)=140+120 & =260 ~mm Hg aligned gathered Mole fraction of B in vapour phase = p_B p_ Total = p_B^ _A p_ Total = 400 0.3 260 =0.462 gathered