MCQ Questions for Class 8 Science Chapter 6 Combustion and Flame with Answers

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Combustion and Flame Class 8 MCQs Questions with Answers

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Question 1.
Which of the following fuels is used for running automobiles?
(a) CNG
(b) Petrol
(c) Both (a) and (b)
(d) Wood

Answer

Answer: (c) Both (a) and (b)


Question 2.
Magnesium burns to form
(a) calcium carbonate
(b) magnesium oxide
(c) calcium oxide
(d) magnesium sulphate

Answer

Answer: (b) magnesium oxide


Question 3.
Coal burns to produce
(a) calcium bicarbonate
(b) magnesium
(c) carbon dioxide
(d) oxygen

Answer

Answer: (c) carbon dioxide


Question 4.
Name the chemical process in which a substance reacts with oxygen to give out heat.
(a) Reaction
(b) Junction
(c) Combustion
(d) All of these

Answer

Answer: (c) Combustion


Question 5.
The substance that undergoes combustion is said to be
(a) burning
(b) flame
(c) charcoal
(d) combustible

Answer

Answer: (d) combustible


Question 6.
Combustible substances are also known as
(a) inflammable
(b) flaming
(c) illuminous
(d) non-flammable

Answer

Answer: (a) inflammable


Question 7.
Which of the following is combustible?
(a) Stone piece
(b) Wood
(c) Glass
(d) None of these

Answer

Answer: (b) Wood


Question 8.
In the sun, light and heat are produced by
(a) chemical reactions
(b) nuclear reactions
(c) burning reactions
(d) bunsen burner

Answer

Answer: (b) nuclear reactions


Question 9.
Lowest temperature at which a substance catches fire is known as
(a) lowest temperature
(b) burning temperature
(c) ignition temperature
(d) flaming temperature

Answer

Answer: (c) ignition temperature


Question 10.
Long, long ago, which of the following trees was used to produce matchsticks?
(a) Mango
(b) Deodar
(c) Banyan
(d) Pine

Answer

Answer: (d) Pine


Question 11.
Which chemical is used in the rubbing surface provided for matchsticks?
(a) Sulphur
(b) Gold
(c) Red phosphorus
(d) White phosphorus

Answer

Answer: (c) Red phosphorus


Question 12.
Substances that have very low ignition temperature and can catch fire easily are called
(a) flammable substances
(b) inflammable substances
(c) combustible substances
(d) all of these

Answer

Answer: (d) all of these


Question 13.
Which of the following is an example of inflammable substance?
(a) Iron
(b) Glass
(c) LPG
(d) Stone

Answer

Answer: (c) LPG


Question 14.
Which of the following are required essentially for producing fire?
(a) Glass, coal, water
(b) Fuel, coal, straw
(c) Fire, wood, burner
(d) Fuel, air, heat

Answer

Answer: (d) Fuel, air, heat


Question 15.
The most common element used as fire extinguisher is
(a) CO2
(b) oxygen
(c) phosphorus
(d) NO2

Answer

Answer: (a) CO2


Question 16.
Baking soda constitutes
(a) hydrogen chloride
(b) sodium oxide
(c) sodium bicarbonate
(d) oxygen

Answer

Answer: (c) sodium bicarbonate


Question 17.
LPG means
(a) Liquefied Petroleum Gas
(b) Liquefied Petrol Gas
(c) Liquid Petrol Godown
(d) Liquid Petroleum Gas

Answer

Answer: (a) Liquefied Petroleum Gas


Question 18.
Phosphorus burns at
(a) room temperature
(b) 100°C
(c) cool temperature
(d) any temperature

Answer

Answer: (a) room temperature


Question 19.
‘Firework’ is an example of
(a) rapid combustion
(b) explosion
(c) spontaneous combustion
(d) slow combustion

Answer

Answer: (b) explosion


Question 20.
The calorific value of ‘hydrogen’ is
(a) 50,000 kJ/kg
(b) 55,000 kJ/kg
(c) 1,50,000 kJ/kg
(d) 6,000 kJ/kg

Answer

Answer: (c) 1,50,000 kJ/kg


Question 21.
Which of these is a combustible substance?
(a) Asbestos
(b) Paper
(c) Stone
(d) Sand

Answer

Answer: (b) Paper


Question 22.
Which of the following is non¬combustible substance?
(a) Alcohol
(b) Coal
(c) Iron
(d) Wood

Answer

Answer: (c) Iron


Question 23.
Which of the following is an inflammable substance?
(a) Coal
(b) Alcohol
(c) Wood
(d) Stone

Answer

Answer: (b) Alcohol


Question 24.
A flame has
(a) one zone
(b) two zones
(c) three zones
(d) four zones

Answer

Answer: (c) three zones


Question 25.
The outermost zone of flame is in colour.
(a) blue
(b) orange
(c) brown
(d) dark

Answer

Answer: (a) blue


Question 26.
Which of the following does not produce flame while burning?
(a) Wax
(b) Petrol
(c) Diesel
(d) Coal

Answer

Answer: (d) Coal


Question 27.
Combustion is a
(a) chemical process
(b) physical process
(c) both of these
(d) none of these

Answer

Answer: (a) chemical process


Question 28.
The lowest temperature at which a substance catches fire is called its
(a) boiling point
(b) melting point
(c) ignition temperature
(d) critical temperature

Answer

Answer: (c) ignition temperature


Question 29.
In the presence of water, ignition temperature of paper
(a) decreases
(b) increases
(c) remains constant
(d) none of these

Answer

Answer: (b) increases


Question 30.
Rapid combustion occurs when
(a) gas bums and produces heat and light
(b) material suddenly bursts into flames
(c) there is evolution of heat
(d) none of these

Answer

Answer: (a) gas bums and produces heat and light


Question 31.
Explosion involves the evolution of
(a) heat
(b) light
(c) sound
(d) all of these

Answer

Answer: (d) all of these


Question 32.
A substance which vaporises during burning gives
(a) sound
(b) flame
(c) combustion
(d) none of these

Answer

Answer: (b) flame


Question 33.
The most common fire extinguisher is
(a) water
(b) carbon dioxide
(c) oxygen
(d) hydrogen

Answer

Answer: (a) water


Question 34.
Unburnt carbon particles cause
(a) stomach infections
(b) respiratory problems
(c) brain infections
(d) throat problems

Answer

Answer: (b) respiratory problems


Question 35.
In the Sun, heat and light are produced by
(a) chemical reactions
(b) nuclear reactions
(c) ionic reactions
(d) none of these

Answer

Answer: (b) nuclear reactions


Question 36.
The head of the safety match contains
(a) antimony trisulphate
(b) potassium chlorate
(c) both (a) and (b)
(d) none of these

Answer

Answer: (c) both (a) and (b)


Question 37.
When a matchstick is struck against the rubbing surface, red phosphorus
(a) converts into white phosphorus
(b) reacts with potassium chlorate
(c) ignites antimony trisulphide
(d) none of these

Answer

Answer: (a) converts into white phosphorus


Question 38.
The amount of heat energy produced on complete combustion of 1 kg of a fuel is called its
(a) combustion value
(b) calorific value
(c) ignition value
d none of these

Answer

Answer: (b) calorific value


Fill in the Blanks

Question 1.
The substance which vapourises during burning gives ……………

Answer

Answer: flame


Question 2.
A good fuel should have …………… calorific value.

Answer

Answer: high


Question 3.
An example of slow combustion is ……………

Answer

Answer: respiration


Question 4.
…………… are substances that release energy on combustion.

Answer

Answer: Fuels


Question 5.
The most common supporter of combustion is ……………

Answer

Answer: oxygen/air


Question 6.
Magnesium burns to change into ……………

Answer

Answer: magnesium oxide


Question 7.
Wood is an example of …………… fuel.

Answer

Answer: solid


Question 8.
…………… is an a example of liquid fuel.

Answer

Answer: Kerosene


Question 9.
Carbon dioxide is …………… than oxygen.

Answer

Answer: heavier


Question 10.
Oxides of …………… and nitrogen causes acid rain.

Answer

Answer: sulphur


Question 11.
The increase in amount of …………… gas in atmosphere results in global warming.

Answer

Answer: carbon dioxide


Question 12.
Inflammable substances have very low …………… temperature.

Answer

Answer: ignition


Question 13.
The …………… zone of a flame is the hottest.

Answer

Answer: non-luminous


Question 14.
During combustion, generally, …………… and …………… energies are produced.

Answer

Answer: heat, light


Question 15.
LPG has a calorific value of …………… kJ/kg.

Answer

Answer: 55,000


Question 16.
A combustible substance cannot catch fire or bum as long as its temperature is lower than its …………………..

Answer

Answer: ignition temperature


Question 17.
The job of a fire extinguisher is to cut off the supply of …………………..

Answer

Answer: air


Question 18.
The type of combustion in a cracker is an example of …………………..

Answer

Answer: explosion


Question 19.
Incomplete combustion of fuels containing carbon releases ………………….. gas.

Answer

Answer: carbon monoxide


Question 20.
Fire produced by oil cannot be controlled by …………………..

Answer

Answer: water


Question 21.
Flame is produced by the ………………….. component of the fuel.

Answer

Answer: volatile


Question 22.
………………….. colour of the flame indicates complete combustion.

Answer

Answer: Blue


True or False

Question 1.
Automobiles run only by using petrol.

Answer

Answer: False


Question 2.
CNG means ‘Connecting Neutral Gas’.

Answer

Answer: False


Question 3.
Coal burns with a flame.

Answer

Answer: False


Question 4.
Magnesium burns to produce magnesium oxide.

Answer

Answer: True


Question 5.
Combustion is a physical process.

Answer

Answer: False


Question 6.
The substance that undergoes combustion is said to be combustible.

Answer

Answer: True


Question 7.
Fuel may be solid, liquid or gas.

Answer

Answer: True


Question 8.
Wood is combustible.

Answer

Answer: True


Question 9.
A matchstick only contains white phosphorus.

Answer

Answer: False


Question 10.
Kerosene is an example of solid fuel.

Answer

Answer: False


Question 11.
For combustion, a substance must attain its ignition temperature.

Answer

Answer: True


Question 12.
The ignition temperature of phosphorus is 25°C.

Answer

Answer: True


Question 13.
LPG is an example of inflammable substances.

Answer

Answer: True


Question 14.
Water is a bad conductor of electricity.

Answer

Answer: False


Question 15.
Fuel, water and heat are three essential requirements for combustion.

Answer

Answer: False


Question 16.
The most common fire extinguisher is water.

Answer

Answer: True


Question 17.
Oxygen is heavier than CO2.

Answer

Answer: False


Question 18.
The middle zone of a flame has yellow colour.

Answer

Answer: True


Question 19.
The calorific value of hydrogen is 1,50,000 kJ/kg.

Answer

Answer: True


Question 20.
Increase in nitrogen gas in atmosphere has led to ‘global warming’.

Answer

Answer: False


Question 21.
Burning of charcoal produces flame with four distinct zones.

Answer

Answer: False


Question 22.
The fuel can only be liquid in nature.

Answer

Answer: False


Question 23.
Sun produces heat and light because of combustion.

Answer

Answer: False


Question 24.
It is easy to burn a piece of wood through matchstick.

Answer

Answer: False


Question 25.
Soda-acid fire extinguisher contains sodium bicarbonate and dilute sulphuric acid.

Answer

Answer: True


Question 26.
Gaseous fuels do not leave any ash after burning.

Answer

Answer: True


Question 27.
Fires in underground coal mines usually occurs due to the explosive combustion.

Answer

Answer: False


Match the following

Column I Column II
1. CNG (a) Nuclear reactions
2. Sun (b) Compressed Natural Gas
3. LPG (c) Liquefied Petroleum Gas
4. Fireworks (d) Explosion
5. Non-luminous zone (e) Least hot
6. Innermost zone (f) Highest calorific value
7. Combustion (g) hottest
8. Phosphorus (h) combustible at 25°C
9. Acid rain (i) exothermic chemical reaction
10. Hydrogen (j) Oxides of nitrogen and sulphur
Answer

Answer:

Column I Column II
1. CNG (b) Compressed Natural Gas
2. Sun (a) Nuclear reactions
3. LPG (c) Liquefied Petroleum Gas
4. Fireworks (d) Explosion
5. Non-luminous zone (g) hottest
6. Innermost zone (e) Least hot
7. Combustion (i) exothermic chemical reaction
8. Phosphorus (h) combustible at 25°C
9. Acid rain (j) Oxides of nitrogen and sulphur
10. Hydrogen (f) Highest calorific value

Column A Column B
1. Fire extinguisher a. Natural gas
2. Fossil fuel b. Cooking gas
3. Oxygen gas c. Inflammable
4. LPG d. Carbon dioxide
5. Alcohol e. Supporter of combustion
Answer

Answer:

Column A Column B
1. Fire extinguisher d. Carbon dioxide
2. Fossil fuel a. Natural gas
3. Oxygen gas e. Supporter of combustion
4. LPG b. Cooking gas
5. Alcohol c. Inflammable

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