NCERT Solutions Class 8 Science Chapter 5

NCERT Solutions for Class 8 Science Chapter 5: Coal and Petroleum 

Science is an essential part of the curriculum, and it is an exciting subject. It is also crucial for the students who wish to make a career in the Science stream. Science opens a lot of opportunities  in engineering courses. 

Chapter 5: Coal and Petroleum is an essential chapter that deals with the fundamental concepts of energies and natural resources. It helps students understand the primary production of oil and crude oil. In addition, students will learn more about the uses of oil and types of energy. Class 8 Science Chapter 5 answers the questions on coal, petroleum, natural gas, and other fossil fuels. 

The NCERT Solutions for Class 8 Science Chapter 5, created by the Extramarks, are available on their website. The solution will guide students through the detailed chapter theory notes, illustrations and Examples and solved questions from past papers. Students can strengthen the concepts of l coal and petroleum chapter and can clear their doubts. 

Besides, Extramarks is one of the best  online learning platforms for students pursuing primary and secondary education.  The NCERT Solutions for Class 8 Science Chapter 5 have been designed by experienced subject matter experts while adhering to the CBSE syllabus. 

The solutions  provide  accurate, up to date and authentic u answers to the questions in the NCERT textbook. Further, students can register themselves on the website and access multiple study materials, without having to look anywhere else.

Students can also regularly visit the Extramarks website for the latest notifications about NCERT syllabus updates. Further, students can also refer to other primary and secondary class solutions, including NCERT Solutions Class 10, NCERT Solutions for Class 11, and NCERT Solutions Class 12.  It will ensure that even the minutest doubt is resolved and the students develop an interest in learning and mastering the topic with ease.

Key Topics Covered In NCERT Solutions for Class 8 Science Chapter 5

Class 8 Science Chapter 5 deals with the fundamentals of coal and petroleum. The chapter starts with an introduction to coal and types of energy. 

Natural Resources

The things that nature provides us are considered natural resources. It contributes to a country’s economy. Natural resources are broadly categorised into two types based on the abundance of various natural resources. 

The following are the two types of natural resources explained in NCERT Solutions for Class 8 Science Chapter 5:

  1. Inexhaustible natural resources:

The infinite resources are abundant in nature, and they are unlikely to be exhausted due to human activities. Sunlight and air are two Examples of inexhaustible natural resources. 

  1. Exhaustible natural resources

We are more likely to deplete these resources if overused. Forests, wildlife, minerals, coal, petroleum, and other natural resources are exhaustible natural resources. 

Fossil Fuel 

Fossil fuels are formed from the decomposition of dead organic matter, such as coal and natural gas. Energy stored in fossil fuels is generally derived from decayed animals and plants that have existed for millions of years. The utilisation of fossil fuels explained in the Extramarks NCERT Solutions for Class 8 Science Chapter 5 is as follows:

  • 40% of the energy used by the industries.
  • The transportation sector uses 24% of the energy.
  • 30% of the energy is used for domestic and other purposes.
  • 6% of the energy used by farms.


Coal is a dark, thick liquid with an obnoxious odour, and it is made up of almost 200 different chemicals. In addition, it is used as starting material for the manufacture of various substances. 

  • Coals are manufactured as synthetic dyes, drugs, explosives, perfumes, plastics, paints, photographic materials, roofing materials, etc. 
  • Bitumen is also used as a petroleum product to metalize roads in place of coal tar. 
  • Naphthalene balls are used to repel moths and  other insects. 
  • Destructive distillation of coal is heating coal, making coke, tar, ammonia, and coal gas. Coal gas is formed when coal is processed to make coke. It is used as a source of energy for street illumination, and it is employed as a heat source rather than a light source. 
  • Ammonia liquor is also one of the by-products formed during the destructive distillation of coal. Just like other coal, it is used to make fertilisers. Coke is a black coloured substance formed from carbon. It is used for manufacturing steel and the extraction of metals. 
  • Peat is a dark fibrous fuel composed of decomposed plant matter. It is the first stage in the formation of coal. The formation of coal is done under high pressure and temperature. The dead vegetation gets converted into coal. This process is called carbonization. In addition, there are four types of coals, including anthracite, bituminous, sub-bituminous, and lignite. 

Students can visit the Extramarks website to refer to more coursework and resources to learn about coal and its formation. Solutions provides a better learning experience  for students and also  enhances their performance in the examinations

Petroleum and Refining of Petroleum

Petrol and diesel are made from natural resources known as petroleum. It is formed from the petra and oleum. In addition, it is made from the organisms that live in the water. 

The organisms perished; their remains sank to the seafloor and were covered in layers of sand and clay. Therefore, the absence of air, high pressure, and temperature turn the dead organisms into petroleum and natural gas over millions of years. 

Petroleum is thick, with a dark colour, and it has an unpleasant odour. Various ingredients contribute to refining petroleum gas, such as gasoline, diesel, lubricating oil, and paraffin wax. In comparison, refining separates the multiple constituents of petroleum. 

Oil refining is separating liquids with different boiling points at different temperatures. 

The following are the uses of the generated products: 

  • Paraffin wax: It is used to make ointments and candles.
  • Bitumen: It is used to make paints.
  • Petrol and diesel: It is used in motor and aviation fuel.
  • Lubricating oil: It is used as a lubricant.
  • Kerosene: It is used as a fuel for stoves and lamps.

Note: The Government shares tips for the conservation of petroleum. It should be carefully used to avoid  shortage in future. 

Natural gas and its uses

  • Natural gas is easy to transfer through pipes, and it can be compressed and stored under high pressure. 
  • It has a high calorific value and does not pollute the environment. 
  • Natural gas such as CNG is used to generate electricity. 
  • CNG has its advantages:
  • It is a cleaner fuel and less polluting. 
  • It is used as a raw material in producing a wide range of chemicals and fertilisers. 

Students can refer to various study materials on the website, Where the subject matter experts  at Extramarks have elaborated on the role of natural gas and its application in more detail. 

NCERT Solutions for Class 8 Science Chapter 5: Exercises &  Solutions

Extramarks is a learning platform which is proven helpful for many students in their examination preparation. Here, students can start with a trial account by registering on the website. Extramarks believes in incorporating joyful learning experiences through its own repository.  

The Solutions cover theoretical explanations and have step-by-step answers to the questions in the NCERT books. Chapter 5- Coal and Petroleum of Class 8 Science has numerous questions, including multiple-choice and descriptive types. Some additional questions at the end of the Solutions help the students clear their doubts on concepts. 

Students can click on the  links given below  to view exercise specific questions and their Solutions as covered in the Extramarks NCERT Solutions for Class 8 Science Chapter 5:

  • Chapter 5: Exercise 5.1 Solutions: 9 Questions

 Besides this, Class 8 Solutions, students can explore NCERT Notes and various other study materials for courses in different Classes:

  • NCERT Solutions Class 1
  • NCERT Solutions Class 2
  • NCERT Solutions Class 3
  • NCERT Solutions Class 4
  • NCERT Solutions Class 5
  • NCERT Solutions Class 6
  • NCERT Solutions Class 7
  • NCERT Solutions Class 8
  • NCERT Solutions Class 9
  • NCERT Solutions Class 10
  • NCERT Solutions Class 11
  • NCERT Solutions Class 12

NCERT Exemplar for Class 8 Science

Class 8 Science is an exciting subject, and it has challenging concepts. Students can develop their understanding of the topic by solving the questions with varying levels of difficulty. . NCERT exemplar consists of different types  of questions. Further, it includes questions with multiple choice answers, long & short answers, and descriptive types of questions. 

The exemplar deals with the sub-topics under the Chapter coal and petroleum. Students can practice the questions given in the exemplar to revise the concepts and speed up their learning to enhance their performance in the exams. . NCERT Class 8 Science exemplar is a brilliant choice for students who want to assess their preparation and strengthen their understanding  of Science as a whole.

The Extramarks NCERT Solutions for Class 8 Science Chapter 5 have questions from Exemplars. It covers some of the essential topics, including destructive distillation of coal, oil extraction, oil production, and types of energies. Thus, students can develop their understanding of each topic with the help of NCERT Solutions created by the Extramarks in-house faculty experts. 

Key Features of NCERT Solutions for Class 8 Science Chapter 5

Some of the essential characteristics of Extramarks NCERT Solutions for Class 8 Science Chapter 5 are:

  • The solutions are highly accurate, reliable  and authentic  as per the latest CBSE guidelines. Along with the NCERT textbook, students should solve questions from NCERT solutions to build a strong foundation
  • These solutions can be the reference material used by the students for their examination preparation. They can get detailed and accurate solutions to questions given in the NCERT textbook, which will help them understand how to solve the different kinds of problems in a step-by-step manner.
  • Students will be able to build their conceptual understanding of fundamental topics that are important for the examination. 
  • The concepts also contain Examples and illustrations  that help to improve  learning among students. 
  • The NCERT solutions for Class 8 Science Chapter 5 enhance students’ innovative learning and efficient answering skills, resulting in better academic scores.

Q.1 What are advantages of using CNG and LPG as fuels?

Ans. The advantages of using LPG as a fuel are as follows:

  1. LPG burns easily with smokeless flame. It is a clean fuel.
  2. LPG has high calorific value.
  3. LPG does not produce any poisonous gases on burning.
  4. LPG does not leave behind any solid residue on burning.

The advantages of using CNG as a fuel are as follows:

  1. CNG burns easily with smokeless flame. It is a clean fuel.
  2. CNG can be used directly for burning in homes and factories.
  3. CNG is used as a fuel for vehicles because it is less polluting.
  4. CNG is used as a fuel in thermal power stations for generating electricity.

Q.2 Name the petroleum product used for surfacing of roads.

Ans. Bitumen is used for surfacing of roads.

Q.3 Describe how coal is formed from dead vegetation. What is the process called?


  1. About 300 million years ago the earth had dense forest in low lying wetlands. Due to natural processes like flooding and earthquakes, forests got buried under the soil. With the passage of time, as more and more soil got deposited on them, the buried plants were compressed. Deep down the earth, pressure and temperature was very high. Under high pressure and temperature, slowly plants got converted into coal.
  2. The slow process of conversion of dead vegetation into coal is called carbonisation.

Q.4 Fill in the blanks.

  1. Fossil fuels are __________, __________ and ___________.
  2. Process of separation of different constituents from petroleum is called _____________.
  3. Least polluting fuel for vehicle is _________.


  1. coal, petroleum, natural gas
  2. refining
  3. CNG

Q.5 Tick True/False against the following statements.

  1. Fossil fuels can be made in the laboratory. (T/F)
  2. CNG is more polluting fuel than petrol. (T/F)
  3. Coke is almost pure form of carbon. (T/F)
  4. Coal tar is a mixture of various substances.(T/F)
  5. Kerosene is not a fossil fuel. (T/F)


  1. Fossil fuels can be made in the laboratory. (F)
  2. CNG is more polluting fuel than petrol. (F)
  3. Coke is almost pure form of carbon. (T)
  4. Coal tar is a mixture of various substances. (T)
  5. Kerosene is not a fossil fuel. (F)

Q.6 Explain why fossil fuels are exhaustible natural resources.

Ans. The amount of fossil fuels available in nature is limited. The formation of fossil fuels takes millions of years. Fossil fuels are made by the action of heat and pressure on the remains of dead vegetation and animals. The rate at which we are using them is very fast as compared to their rate of formation. Therefore, fossil fuels are exhaustible natural resources.

Q.7 Describe characteristics and uses of coke.

Ans. Coke is a black porous substance. It is obtained as residue during destructive distillation of coal. The characteristics of coke are as follows:

  1. Coke is an almost pure form of carbon.
  2. It burns almost with no smoke.
  3. It is a non-conductor of heat and electricity.

Uses of coke are as follows:

  1. Coke is used in the extraction of metals.
  2. It is also used in the manufacturing of steel.

Q.8 Explain the process of formation of petroleum.


  • Petroleum originated from the remains of sea organisms.
  • When sea organisms died, they got buried at the bottom of sea.
  • With passage of time, their bodies got covered with mud.
  • Pressure and temperature rose as they got buried lower and lower.
  • Due to the effect of heat, pressure and action of bacteria in the absence of air, the buried remains decomposed very slowly forming petroleum.

Q.9 The following table shows the total power shortage in India from 1991-1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.

S.No. Year Shortage (%)
1 1991 7.9
2 1992 7.8
3 1993 8.3
4 1994 7.4
5 1995 7.1
6 1996 9.2
7 1997 11.5


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FAQs (Frequently Asked Questions)
1. Which are the essential topics covered in NCERT Solutions for Class 8 Science Chapter 5?

The sub topics covered in the Chapter 5 Class 8 are: 

  • Introduction to coal and petroleum
  • Energy
  • Types of energy
  • Energy conversion from one form to another
  • Natural Resource
  • Coal Formation
  • Destructive distillation of coal

2. What are the benefits of studying from Extramarks NCERT Solutions?

The Solutions guide from Extramarks helps students build a foundation on the subtopics in Class 8 Science Chapter 5. It is designed to help students study the entire subject quickly and  with 100% accuracy. It is written in an easy to understand language by the subject matter experts. It is a thoroughly researched material made as per the CBSE examination guidelines.

3. Why is Extramarks NCERT Class 8 Science Chapter 5 Solutions crucial?

The NCERT Solutions for Class 8 Science Chapter 5 prepare  the answers for students so that they can  easily  understand and comprehend. A team of experienced subject experts  prepare  the solution guide. It will ensure that even the minutest doubt is resolved and the students develop an interest in learning and mastering the topic with ease.