Q.
PA and PB are the vapour pressure of pure liquid components A and B respectively of an ideal binary solution. If xA represents the mole fraction the total pressure of the solution will be :
Total pressure PT=PA+PB
now PA=PAxA PB=PBxB
Substituting the values of PA and PB in eq. (i) PT=PAxA+PBxB [xA+xB=1orxA=1−xBorxB=1−xA] =PAxA+PB−PBxA ∴PT=PB+xA(PA−PB)