Benzene and toluene form nearly ideal solutions. At 20° C, the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at 20° C for a solution containing 78 g of benzene and 46 g of toluene in torr is:

Question

Benzene and toluene form nearly ideal solutions. At 20° C, the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at 20° C for a solution containing 78 g of benzene and 46 g of toluene in torr is: (A) 53.5 (B) 37.5 (C) 25 (D) 50

Tardigrade Admin · Accepted Answer

Mixture contains 78g benzene = 1 mole benzene and 46 g toluene = 0.5 mole toluene
Total mole of benzene and toluene = 1.5 mol
Mole fraction of benzene in mixture

= \frac{1}{1.5} = \frac{2}{3}

VP of benzene

p_{b}^{\circ} = 75

torr

∴

partial vapour pressure of benzene

= p_{b}^{\circ} X_{b}

= 75 \times \frac{2}{3} = 50

torr

Q. Benzene and toluene form nearly ideal solutions. At 20∘ C, the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at 20∘ C for a solution containing 78 g of benzene and 46 g of toluene in torr is:

53.5

37.5

25

50

Mixture contains 78g benzene = 1 mole benzene and 46 g toluene = 0.5 mole toluene Total mole of benzene and toluene = 1.5 mol Mole fraction of benzene in mixture =1.51​=32​ VP of benzene pb∘​=75 torr ∴ partial vapour pressure of benzene =pb∘​Xb​ =75×32​=50 torr

Q. Benzene and toluene form nearly ideal solutions. At 20 $^{\circ}$ C, the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at 20 $^{\circ}$ C for a solution containing 78 g of benzene and 46 g of toluene in torr is: