Heptane and octane form an ideal solutio | Class 12 Chemistry Chapter Solutions, Solutions NCERT Solutions

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter Solutions. This page offers a step-by-step solution to the specific question from Exercise 2, Question 16: . With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 16:

Heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components are 105.2 kPa and 46.8 kPa respectively. What will be the vapour pressure of a mixture of 26.0 g of heptane and 35 g of octane?

Answer:

Vapour pressure of heptane p10 = 105.2 kPa

Vapour pressure of octane p20= 46.8 kPa

As we know that, Molar mass of heptane (C7H16) = 7 × 12 + 16 × 1 = 100 g mol - 1

∴ Number of moles of heptane = 26/100 mol  = 0.26 mol

Molar mass of octane (C8H18) = 8 × 12 + 18 × 1 = 114 g mol - 1

∴ Number of moles of octane = 35/114 mol = 0.31 mol

Mole fraction of heptane, x1 = 0.26 / 0.26 + 0.31

= 0.456

And, mole fraction of octane, x2 = 1 - 0.456 = 0.544

Now, partial pressure of heptane, p1 = x2 p20

= 0.456 × 105.2

= 47.97 kPa

Partial pressure of octane,p2 = x2 p20

= 0.544 × 46.8 = 25.46 kPa

Hence, vapour pressure of solution, ptotal  =  p1 + p2

= 47.97 + 25.46

= 73.43 kPa


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about Solutions.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

Latest Blog Posts

Stay updated with our latest educational content and study tips

How to Recognize and Prevent Online Scams Targeting Kids

The internet is full of entertaining apps, games and movies for kids of all ages. However not everything online is safe. Hidden among these entertaining platforms are internet frauds that target children with phony gifts, free game currencies or friendly looking people. As a parent, you may believe that scammers only target adults; yet children […]

Read More

How to Talk to Kids About Screen Time rules Without Conflict

Did you know? The average teenager spends 7 – 8 hours daily on screens . That’s almost like working a full – time job in front of a screen – except kids aren’t earning a paycheck; instead they’re often trading sleep, focus and health for digital time. In today’s world, screens are everywhere – TV, […]

Read More

10 Online Safety Rules Every Parent Should Teach Their Kids

Children are spending more time online than ever before in today’s digital world.  The internet provides enjoyment and knowledge through social media and online education, but it also has unspoken risks. Parents frequently worry about harmful information, internet predators and cyberbullying. The good news is that most problems can be avoided by teaching children basic […]

Read More

Top 8 internet Safety terms Parents Must Know to Keep Children Safe

The internet has become an inseparable part of our daily lives . From online learning to social media most systems we use today are fully digitized and processed by computers. While this digital shift has created immense opportunities it has also opened new challenges – especially for children and teenagers. Social media, gaming platforms and […]

Read More

Comments

  • NATS
  • Oct 04, 2023

35/114=0.30 .....but why 0.31?


  • Nayan M J
  • Jun 26, 2019

It was a suitable answer


  • Fucker
  • May 15, 2019

There is a mistake for finding partial pressure. It should have been written Pa = xap°a


  • Aakarshan
  • Apr 24, 2019

The yellow background soothes me.


  • chutiya
  • Apr 22, 2019

dhanywad


  • Procrastinator
  • Mar 12, 2019

God bless ur soul


  • Shivam Yadav
  • Mar 09, 2019

Wow thanks


  • Alfin
  • Mar 01, 2019

p1 = x2 p20??


  • Samoon karamat
  • May 30, 2018

Thanks for this help ....best &simple solution


  • Rama
  • Oct 17, 2017

Thanks for this help Best site!!!!!!


Add Comment

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 2 , Question 16: Heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid componen....