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 a 20^{\circ}C for a solution containing 78 g of benzene and 46 g of toluene in torr is

  • Option 1)

    50

  • Option 2)

    25

  • Option 3)

    37.5

  • Option 4)

    53.5

 

Answers (1)

As we learnt in

Rault's Law -

The total vapour pressure of binary mixture of miscible liquids be having ideally is given by

P_{T}= P_{A}^{0}x_{A}+P_{B}^{0}x_{B}

Where x_{A}  and  x_{B} are mole fraction of A and B in liquid phase.

 

 

- wherein

P_{A}^{0}  and P_{B}^{0} are vapour pressures of pure liquids.

 

 

According to Raoult's law ,P_{B}= P^{0}_{B}X_{B} \; \; \; \; \; \; P^{0}_{B}= 75\: torr

X_{B}= \frac{78/78}{\left ( 78/78 \right )+\left ( 46/92 \right )}= \frac{1}{1+0.5}= \frac{1}{1.5}

P_{B}= 75\times \frac{1}{1.5}= 50 \; torr

Correct option is 1.

 


Option 1)

50

This is the correct option.

Option 2)

25

This is an incorrect option.

Option 3)

37.5

This is an incorrect option.

Option 4)

53.5

This is an incorrect option.

Preparation Products

Knockout JEE Main April 2021 (One Month)

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 14000/- ₹ 4999/-
Buy Now
Knockout JEE Main May 2021

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 22999/- ₹ 9999/-
Buy Now
Test Series JEE Main May 2021

Unlimited Chapter Wise Tests, Unlimited Subject Wise Tests, Unlimited Full Mock Tests, Get Personalized Performance Analysis Report,.

₹ 6999/- ₹ 2999/-
Buy Now
Knockout JEE Main May 2022

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 34999/- ₹ 14999/-
Buy Now
JEE Main Rank Booster 2021

Booster and Kadha Video Lectures, Unlimited Full Mock Test, Adaptive Time Table, 24x7 Doubt Chat Support,.

₹ 13999/- ₹ 6999/-
Buy Now
Boost your Preparation for JEE Main 2021 with Personlized Coaching
 
Exams
Articles
Questions