Combustion and Flame — Class 8 MCQs with Answers
Class 8 CBSE Science · Chapter 104
Pre-2026 syllabusThis chapter is from the older NCERT book. See the 2026-27 Class 8 Science chapters →
72 practice questions · 24 Easy · 24 Medium · 24 Hard · Updated
Jump to the 6 solved questions
Practise the most important Class 8 CBSE Science questions from Chapter 104, "Combustion and Flame". You get 6 timed quizzes made from 72 NCERT-based MCQs, with answers and explanations. The questions are split into 24 Easy, 24 Medium and 24 Hard. Warm up on the basics, then move on to the exam-level questions that top scorers in CBSE Board exams get right.
To score well in "Combustion and Flame", focus on clear concepts in physics, chemistry and biology basics. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This helps you stay accurate when time is short, just as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.
Use this chapter for focused revision. Start with the Easy set to check your basics on Combustion and Flame, then move to Medium and Hard to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 8 Science mastery score. Try the 6 sample questions below: tap an option to see the answer and a worked explanation. Sign in free to start practising.
Combustion and Flame — important questions & MCQs with answers (Class 8 Science)
6 solved questions from this chapter's difficulty levels, each with its answer and explanation. Tap an option to check yourself.
0 of 6 answered
- Q1 of 6Easy
Combustion is a chemical process in which a substance reacts with:
Show answerHide answer
Answer: Oxygen, giving out heat
Explanation: In combustion a substance reacts with oxygen to produce heat (and often light).
- Q2 of 6Easy
Burning of LPG in a stove is an example of:
Show answerHide answer
Answer: Rapid combustion
Explanation: LPG burns rapidly, producing heat and light at once — rapid combustion.
- Q3 of 6Medium
Why does charcoal glow but does not produce a flame, while a candle gives a flame?
Show answerHide answer
Answer: Charcoal does not vaporise, while candle wax vaporises and burns as a flame
Explanation: Only vaporising fuels burn with a flame; non-vaporising charcoal merely glows.
- Q4 of 6Medium
Why is CNG considered a better fuel than wood?
Show answerHide answer
Answer: It has a higher calorific value and burns cleanly
Explanation: CNG releases more heat per kg and burns more completely with less pollution than wood.
- Q5 of 6Hard
Why is water dangerous on an electrical fire but CO2 is safe?
Show answerHide answer
Answer: Water conducts electricity (risk of shock); CO2 cuts off oxygen without conducting
Explanation: Water conducts electricity, risking shock and spread; CO2 smothers the fire and does not conduct.
- Q6 of 6Hard
Assertion (A): A candle goes out when covered by a glass jar. Reason (R): Combustion needs a continuous supply of oxygen. Choose the correct option.
Show answerHide answer
Answer: Both A and R are true and R explains A
Explanation: The jar cuts off oxygen; since combustion needs oxygen, the candle goes out — R explains A.
Combustion and Flame notes: key concepts (Class 8 Science)
This chapter covers combustion, the conditions and types of burning, the structure of a flame, and fuels with their efficiency.
- Combustion
- A chemical process in which a substance reacts with oxygen, giving out heat (and often light).
- Conditions for combustion
- A combustible substance, a supporter (oxygen), and reaching the ignition temperature.
- Types of combustion
- Rapid (e.g. burning gas), spontaneous (e.g. phosphorus) and explosive (e.g. firecrackers).
- Structure of a flame
- Three zones — the innermost (unburnt, dark), middle (yellow, partial combustion) and outermost (blue, complete combustion, hottest).
- Fuel efficiency
- Calorific value is the heat produced per kg of fuel; an ideal fuel is cheap, safe and burns cleanly.
Start this chapter free
You have 6 to try above. Sign in with Google (no card needed). You get 1 Easy + 1 Medium quiz on every chapter, free for good (up to 6 quizzes a day) — plus a free Hard quiz when you score 70%+ on a Medium quiz (1 per subject), and the formulas & exam tips.
This chapter has 72 questions (24 Easy · 24 Medium · 24 Hard), with timed scoring and instant feedback. The rest unlock with the ₹999/year plan.
Start with the questions above. The full quiz opens here after.
Combustion and Flame — FAQs
What are the key concepts in Class 8 Science Combustion and Flame?+
This chapter covers combustion, the conditions and types of burning, the structure of a flame, and fuels with their efficiency. Key ideas include Combustion, Conditions for combustion, Types of combustion, Structure of a flame, Fuel efficiency.
What does Class 8 Science Chapter 104 (Combustion and Flame) cover on XamBaaz?+
It has 72 NCERT-based MCQs on "Combustion and Flame": 24 Easy, 24 Medium and 24 Hard. Together they make 6 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE Board exams.
Are these "Combustion and Flame" questions free to practise?+
Yes. Sign in with Google to practise "Combustion and Flame" free. Full unlimited access is ₹999/year. One year from the day you pay. You stay in Class 8 till 31 March; on 1 April your account moves up to Class 9 and the rest of your year carries over. No chapter is charged separately.
How should I revise "Combustion and Flame" for the exam?+
Start with the Easy quiz to check your basics, then try Medium and Hard to practise applying them. There are 6 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.
Are these "Combustion and Flame" MCQs available with answers?+
Yes. 6 sample questions are on this page with answers: tap an option, or "Show answer", to see the correct option and a step-by-step explanation. Sign in free with Google to start practising, with instant scoring.
Is there negative marking in the "Combustion and Flame" quizzes?+
Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.
What are the important questions from Combustion and Flame (Class 8 Science)?+
The questions that matter most test Combustion, Conditions for combustion, Types of combustion, Structure of a flame, Fuel efficiency. This page shows 6 solved important MCQs with answers and explanations. Sign in to practise all 72 questions on the chapter as timed quizzes.
Is there an online quiz for Combustion and Flame?+
Yes — Class 8 Science Combustion and Flame has timed online quizzes at Easy, Medium and Hard levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.
Are there question answers and extra questions for Combustion and Flame (Class 8 Science)?+
Yes. This page has 6 solved questions on Combustion and Flame, each with the correct answer and a short explanation. Sign in to practise all 72 questions on the chapter as timed quizzes.