Last Updated on April 17, 2024 by XAM CONTENT
Hello students, we are providing assertion reason questions for class 8 science. Assertion reason questions are the new question format that is introduced in CBSE board. The resources for assertion reason questions are very less. So, to help students we have created chapterwise assertion reason questions for class 8 science. In this article, you will find assertion reason questions for cbse class 8 science chapter 4 combustion and flame.
| Chapter | Combustion and Flame |
| Type of Questions | Assertion Reason Questions |
| Nature of Questions | Competency Based Questions |
| Board | CBSE |
| Class | 8 |
| Subject | Science |
| Useful for | Class 8 Studying Students |
| Answers provided | Yes |
| Difficulty level | Mentioned |
| Important Link | Class 8 Science Chapterwise Assertion Reason |
Assertion Reason on Combustion and Flame
Questions:
Q.1. Assertion (A): Water is commonly used to control fire.
Reason (R): Any fire can be extinguished with water.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A)
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
Difficulty Level: Medium
Ans. Option (c) is correct.
Explanation: The most common fire extinguisher is water. The Fire brigade pours water on the fire. Water cools the combustible material so that its temperature is brought below its ignition temperature. This prevents the fire from spreading. But water works only when things like wood and paper are on fire. If electrical equipment is on fire, water may conduct electricity and harm those trying to extinguish the fire. Water is also not suitable for fires involving oil and petrol. This is because as water is heavier than oil, it sinks below the oil and oil keeps burning on top.
Q.2. Assertion (A): Acid rains are caused by emissions of sulphur dioxide and nitrogen oxide.
Reason (R): Acid rain is dangerous for earth.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A)
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
Difficulty Level: Medium
Ans. Option (a) is correct.
Explanation: Acid rains are caused by emissions of sulphur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acid. The concentration of rain has a pH value less than 5.5. Acid rain causes plant burning, skin cancer, many respiratory diseases and so on. Due to acid rain many historical buildings also get destroyed.
Also Check
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- Reaching the Age of Adolescence Assertion Reason for Class 8 Science
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- Conservation of Plants and Animals Assertion Reason for Class 8 Science
- Combustion and Flame Assertion Reason for Class 8 Science
- Coal and Petroleum Assertion Reason for Class 8 Science
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- Crop Production and Management Assertion Reason for Class 8 Science
Topics from which assertion reason questions may be asked
- Learning what is meant by combustion?
- Knowing types of combustion.
- Discuss various methods used to control fire.
- Learning the structure of flame.
- To know more about fuel and fuel efficiency.
We use various kinds of fuel such as petrol, diesel, CNG, LPG, coal, wood etc., in our daily life. Some of these fuels burn with a flame while some do not. This chapter deals with the chemical processes involved in burning and the type of flames produced in the processes. So based on this, the above topic list is provided.
