On mixing, heptane and octane form an ideal solution. At 373 K, the vapour pressure of the two liquid components (heptane and octane) are 105 kPa and 45 kPa respectively. Vapour pressure of the solution obtained by mixing 25.0 g of heptane and 35 g of octane will be (molar mass of heptane = 100 g mol-1 and of octane = 114 g mol-1 )
144.5 kP
72.0 kP
36.1 kP
96.2 kPa
As we learnt in
Rault's Law -
The total vapour pressure of binary mixture of miscible liquids be having ideally is given by
Where and are mole fraction of A and B in liquid phase.
- wherein
and are vapour pressures of pure liquids.
p = 71.92
Correct option is 2.
Option 1)
144.5 kP
This is an incorrect option.
Option 2)
72.0 kP
This is the correct option.
Option 3)
36.1 kP
This is an incorrect option.
Option 4)
96.2 kPa
This is an incorrect option.
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