0

Guest

Courses New

At 25 degree Celsius, the vapour pressure of pure water is 23.76 mm Hg and that of an aqueous dilute solution of urea is 22.98 mm Hg .calculate the molality of this solution

At 25 degree Celsius, the vapour pressure of pure water is 23.76 mm Hg and that of an aqueous dilute solution of urea is 22.98 mm Hg .calculate the molality of this solution

Grade:12

2 Answers

varun
304 Points
6 years ago
HELLO ABHISHEK,
we know that,
total vapour pressure = pure vapour pressure X mole fraction
22.98  =  23.76 X Xw
therefore,
Xw = 22.98/23.76
       =Nw/Nw+ Na
so,
22.98/23.76--22.98
====>Nw/Na
therefore,
Na/Nw = 23.76--22.98/22.98
 
NOW,
molality = Na/mass of water in kg
             =Na/Nw X 18X10^-3
 so molality = 23.76--22.98/22.98 X 18X10^-3
so the final answer = 0.001X 10^-3
THANK YOU
Kushagra Madhukar
askIITians Faculty 628 Points
3 years ago
Dear student,
Please find the solution to your problem below.
 
We know that,
total vapour pressure = pure vapour pressure X mole fraction
22.98  =  23.76 X Xw
therefore,
Xw = 22.98/23.76
       =Nw/Nw+ Na
so,
22.98/23.76--22.98
====>Nw/Na
therefore,
Na/Nw = 23.76--22.98/22.98
 
NOW,
molality = Na/mass of water in kg
             =Na/Nw X 18X10^-3
 so molality = 23.76--22.98/22.98 X 18X10^-3
so the final answer = 0.001X 10^-3
 
Hope it helps.
Thanks and regards,
Kushagra

Think You Can Provide A Better Answer ?

Other Related Questions on Physical Chemistry

View all Questions »

ASK QUESTION

Get your questions answered by the expert for free

Answer and earn gift vouchers

Win Gift vouchers upto Rs 500/-

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Click Here Know More

Complete Self Study Package designed by Industry Leading Experts

Click Here Know More

Live 1-1 coding classes to unleash the Creator in your Child

Click Here Know More

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Click Here Know More