The Total pressure observed by mixing two liquid A and B is 350 mm Hg when their mole fractions are 0 . 7 and 0 . 3 respectively. The Total pressure becomes 410 mm Hg if the mole fractions are changed to 0 . 2 and 0 . 8 respectively for A and B . The vapour pressure of pure A is ______ mm Hg . (Nearest integer) Consider the liquids and solutions behave ideally

Step-by-step solution

Let Vapour pressure of pure A be P A o Let Vapour pressure of pure B be P B o Using Raoult's law and Dalton's law: When   X A     =   0 . 7   &   X B     =   0 . 3 P s   =   350 ⇒   P A o   × 0 . 7   +   P B o   × 0 . 3   =   350         . . . . ( i ) When   X A     =   0 . 2   &   X B   =   0 . 8   P s   =   410 ⇒