Pressure over ideal binary liquid mixture containing 10 moles each of liquid A and B is gradually decreased isothermally. If P∘A=200 mm Hg and P∘B=100 mm Hg, the pressure at which half of the liquid is converted into vapour is:
a. 150 mm Hg
b. 166.5 mm Hg
c. 133 mm Hg
d. 141.4 mm Hg