Question

The vapour pressures of two volatile liquids A and B at 25°C are 50 Torr and 100 Torr, respectively. If the liquid mixture contains 0.3 mole fraction of A, then the mole fraction of liquid B in the vapour phase is `x/17`. The value of x is ______.

पर्याय

• 10

• 19

• 5

• 14

Answer 1

The vapour pressures of two volatile liquids A and B at 25°C are 50 Torr and 100 Torr, respectively. If the liquid mixture contains 0.3 mole fraction of A, then the mole fraction of liquid B in the vapour phase is `x/17`. The value of x is 14.

Explanation:

`"P"_"Total" = "P"_"A"^circ x_"A" + "P"_"B"^circ x_"B"`

= 50 × 10.3 + 100 × 10.7 = 85 torr

P₂ = y_B + P_Total

70 = y_B × 85

y_B = `70/85 = 14/17`

∴ x = 14; y = 17