The air is a mixture of a number of gase | Class 12 Chemistry Chapter Solutions, Solutions NCERT Solutions

Current NCERT chapter

Academic session 2026-27, Chapter 1 in the current curriculum.

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 39:

The air is a mixture of a number of gases. The major components are oxygen and nitrogen with approximate proportion of 20% is to 79% by volume at 298 K. The water is in equilibrium with air at a pressure of 10 atm. At 298 Kif the Henry's law constants for oxygen and nitrogen are 3.30 x 107 mm and 6.51 x 107mm respectively, calculate the composition of these gases in water.

. 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 39:

The air is a mixture of a number of gases. The major components are oxygen and nitrogen with approximate proportion of 20% is to 79% by volume at 298 K. The water is in equilibrium with air at a pressure of 10 atm. At 298 Kif the Henry's law constants for oxygen and nitrogen are 3.30 x 107 mm and 6.51 x 107mm respectively, calculate the composition of these gases in water.

Answer:

Percentage of oxygen (O2) in air = 20 %

Percentage of nitrogen (N2) in air = 79%

Also, it is given that water is in equilibrium with air at a total pressure of 10 atm, that is, (10 × 760) mm Hg = 7600 mm Hg

Therefore, Partial pressure of oxygen, po2 = 20/100 *7600

=1520 mm Hg

Partial pressure of nitrogen,pN2 = 79/100 *7600

= 6004 mmHg

Now, according to Henry's law:

p = KH.x

For oxygen:

po2  = KH. xO2

⇒xO2 = po2 / KH

= 1520 / 3.30 X 107

= 4.61 10-5

For nitrogen:

pN2 = KH.xN2

⇒xN2 = pN2 / KH

= 6004 / 6.51 x 107

= 9.22 x 10-5

Hence, the mole fractions of oxygen and nitrogen in water are 4.61 ×10 - 5 and 9.22 × 10 - 5 respectively.


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 Build a Career in Data Analytics Without a Computer Science Degree

All businesses are gathering information on customers, products, employees, and expenditures, and someone must make decisions based on the data. That individual is the data analyst. Unlike many career changers imagine, the job is open to a broader cross-section of the population than a typical career change. A lot of working analysts trained in commerce, … Read more

Read More

Life Insurance vs Health Insurance: Why Families May Need Both

Are often purchased, talked and planned as being a replacement for another. They aren’t. One safeguards your family’s income in your absence and the other safeguards your family’s savings in the event that someone becomes ill. An examination of what they do, what they do not do, and why they are missing it when one … Read more

Read More

Home Loan vs Savings: Compare the Costs Before Buying a Home

Pay upfront, or pay off less and over time? The truth depends on four factors most consumers will never compare at the same time: the interest rate on the house loan, the interest rate on the savings account, the rate of home price appreciation, and the cost of renting the home until you actually buy … Read more

Read More

Business After 30 or a Stable Job: Which Path Should You Choose?

Thirty is when the question starts to get raised and you’re able to do something because you know you have the experience—you know you have the responsibility. Here are some ways to consider the choice based on a realistic assessment without idealizing either aspect. Restlessness is one of those things that appears in your early … Read more

Read More

Related Student Tools

Comments

  • Bhumika Rajawat
  • Aug 11, 2019

Y r v not considering volume, when they have given proportions by volume??


  • Jaydeep kalita
  • Apr 18, 2019

The subscript 2 must be written nicely to make it more convineint.


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 39: The air is a mixture of a number of gases. The major components are oxygen and nitrogen with approxi....

Ask a Question
Keep learning

Discover More on SaralStudy

Explore all articles