MCQ Questions for Class 8 Science Chapter 6 Combustion and Flame
Solving the Combustion and Flame Multiple Choice Questions of Class 8 Science Chapter 6 MCQ can be of extreme help as you will be aware of all the concepts. These MCQ Questions on Combustion and Flame Class 8 with answers pave for a quick revision of the Chapter thereby helping you to enhance subject knowledge. Have a glance at the MCQ of Chapter 6 Science Class 8 and cross-check your answers during preparation.
Question 1.
Which of the following fuel produces ash on burning:
(a) wood
(b) LPG
(c) petrol
(d) diesel
Answer
(a) wood
Wood produces ash on burning.
Question 2.
The zone of a flame used by goldsmith for melting gold and silver is:
(a) innermost zone
(b) middle zone
(c) outermost zone
(d) all of these
Answer
(c) outermost zone
The zone of a flame used by goldsmith for melting gold and silver is outermost zone because it is the hottest zone.
Question 3.
Can the process of rusting he called combustion ?
(a) yes
(b) no
(c) can’t say
(d) none of these
Answer
(a) yes
Yes, the process of rusting can be called combustion because it produces heat.
Question 4.
Is heat and light produced by Sun a combustion process?
(a) yes
(b) no
(c) can’t say
(d) none of these
Answer
(b) no
No, heat and light produced by sun is not a combustion process.
Question 5.
Heat and light produced in the sun is by:
(a) combustion
(b) nuclear reactions
(c) burning
(d) none of these
Answer
(b) nuclear reactions
Heat and light produced in the sun is by nuclear reactions.
Question 6.
Ignition temperature is the:
(a) temperature at which a substance catches fire
(b) highest temperature at which a substance catches fire
(c) lowest temperature at which a substance catches fire
(d) none of these
Answer
(c) lowest temperature at which a substance catches fire
Ignition temperature is the lowest temperature at which a substance catches fire
Question 7.
Which of them can be easily burnt with the help of a matchstick?
(a) wooden chips
(b) straw
(c) wooden log
(d) all of them
Answer
(b) straw
Straw can be easily burnt with the help of a matchstick because the ignition temperature of straw is very less and heat produced from lighted matchstick is more than the ignition temperature of straw and therefore it starts burning.
Question 8.
A mgtchstjck does not catch fire on its own at room temperature because its:
(a) ignition temperature is more than room temperature
(b) ignition temperature is less than room temperature
(c) ignition temperature is same as room temperature
(d) none of these
Answer
(a) ignition temperature is more than room temperature
A matchstick does not catch fire on its own at room temperature because its ignition temperature is more than room temperature.
Question 9.
Which of the following gas extinguishes fire:
(a) oxygen
(b) hydrogen
(c) carbon dioxide
(d) nitrogen
Answer
(c) carbon dioxide
Carbon dioxide gas extinguishes fire.
Question 10.
Combustion that takes place at a very fast rate is called:
(a) rapid combustion
(b) spontaneous combustion
(c) explosion
(d) none of these
Answer
(a) rapid combustion
Combustion that takes place at a very fast rate is called rapid combustion.
Question 11.
The coldest zone of candle is:
(a) the middle zone
(b) the innermost zone
(c) the outermost zone
(d) none of these.
Answer
(b) the innermost zone
The coldest zone of candle is the innermost zone.
Question 12.
Smoke contains:
(a) unburnt carbon particles
(b) burnt carbon particles
(c) unburnt sulphur particles
(d) unburnt lead particles.
Answer
(b) burnt carbon particles
Smoke contains unburnt carbon particles.
Question 13.
The colour of the non-luminous zone is:
(a) white
(b) yellow
(c) blue
(d) black
Answer
(c) blue
The colour of the non-luminous zone is blue.
Question 14.
Which of the following fuel has the highest calorific value:
(a) cow dung cake
(b) Wood
(c) coal
(d) Petrol
Answer
(d) Petrol
Petrol has higher calorific value than petrol.
Question 15.
The fuel which replaces use of diesel and petrol as fuels in automobiles is:
(a) LPG
(b) biogas
(c) CNG
(d) none of these
Answer
(c) CNG
CNG has replaced use of diesel and petrol as fuels in automobiles because it is non-pollutant fuel.
Question 16.
Which of following does not produce flame on burning:
(a) LPG
(b) charcoal
(c) paper
(d) kerosene
Answer
(b) charcoal
LPQ paper and kerosene produces flame on burning whereas charcoal does not produce flame on burning.
Question 17.
Which of the following is best fuel for automobiles:
(a) petrol
(b) CNG
(c) diesel
(d) kerosene
Answer
(b) CNG
CNG is best fuel for automobiles as it produces pollutants in very small amounts.
Question 18.
which of the following causes global warming:
(a) carbon dioxide
(b) carbon monoxide
(c) nitrogen dioxide
(d) none of these
Answer
(a) carbon dioxide
Carbon dioxide causes global warming.
Question 19.
The unit of calorifie virtue is:
(a) kilojoules per kg
(b) joules per kg
(c) kilojoules per grain
(d) joules per gram
Answer
(a) kilojoules per kg
The unit of calorific value is Kilojoules per kg.
Question 20.
The hottest zone of candle fleme is:
(a) outermost zone
(b) in memos zone
(c) middle zone
(d) all of these
Answer
(a) outermost zone
The hottest zone of candle flame is outermost zone.
Question 21.
A chemical process in which a substance reacts with oxygen to give off heat is called.
(a) reduction
(b) evaporation
(c) combustion
(d) none of these
Answer
(c) combustion
Combustion is a chemical process in which a substance reacts with oxygen to give off heat.
Question 22.
Which of the following burns with flame:
(a) coal
(b) cow dung
(c) candle
(d) all of these
Answer
(c) candle
Candle burns with a flame, coal, cow dung does not burn with a flame.
Question 23.
Magnesium burns in air to form
(a) magnesium oxide
(b) heat
(c) light
(d) all of these
Answer
(d) all of these
Magnesium bums in air to form magnesium oxide, heat and light.
Question 24.
Which of the following substance is not combustible:
(a) matchstick
(b) straw
(c) charcoal
(d) glass
Answer
(d) glass
Glass is not combustible. Matchstick, straw and charcoal are combustible.
Question 25.
In which of the following conditions combustion takes place:
(a) the presence of a combustible substance
(b) the presence of air with sufficient amount of oxygen
(c) the temperature of combustible substance should be more than its ignition temperature
(d) all the above conditions are necessary
Answer
(d) all the above conditions are necessary
The conditions under which combustion takes place is the presence of a combustible substance, air with sufficient amount of oxygen and ignition temperature of the combustible substance.
Question 26.
Which of the following is smoke free fuel:
(a) wood
(b) LPG
(c) charcoal
(d) coal
Answer
(b) LPG
LPG is smoke free fuel, wood, charcoal and coal produces smoke on burning.
Question 27.
Coal mainly contains:
(a) carbon
(b) nitrogen and Sulphur
(c) carbon, hydrogen and nitrogen
(d) none of these
Answer
(a) carbon
Coal mainly contains carbon.
Question 28.
Which poisonous gas is formed as a result of incomplete combustion ?
(a) carbon monoxide
(b) coal gas
(c) carbon dioxide
(d) nitrogen oxide
Answer
(a) carbon monoxide
The poisonous gas formed as a result of incomplete combustion is carbon monoxide.
Question 29.
The natural solid fuel is:
(a) coal
(b) charcoal
(c) coke
(d) LPG
Answer
(a) coal
The natural solid fuel is coal.
Question 30.
Which of the following give us pollution free environment on burning:
(a) wood
(b) kerosene
(c) cow dung cakes
(d) biogas
Answer
(d) biogas
Biogas gives us pollution free environment on burning.
Match the Column-A with Column-B:
Question 1.
| Column-A | Column-B |
| (a) Charcoal | (i) Inflammable substance |
| (b) Iron nails | (ii) Combustible substance |
| (c) Petrol | (iii) Non-combustible substance |
Answer
| Column-A | Column-B |
| (a) Charcoal | (ii) Combustible substance |
| (b) Iron nails | (iii) Non-combustible substance |
| (c) Petrol | (i) Inflammable substance |
Question 2.
| Column-A | Column-B |
| (a) Rapid Combustion | (i) When a sudden reaction takes place with the evolution of heat, light, sound and large amount of gas. |
| (b) Spontaneous Combustion | (ii) When gas burns rapidly and produces heat and light. |
| (c) Explosion | (iii) When a material suddenly bursts into flames, without , the application of any apparent cause |
Answer
| Column-A | Column-B |
| (a) Rapid Combustion | (ii) When gas burns rapidly and produces heat and light. |
| (b) Spontaneous Combustion | (iii) When a material suddenly bursts into flames, without , the application of any apparent cause |
| (c) Explosion | (i) When a sudden reaction takes place with the evolution of heat, light, sound and large amount of gas. |
Question 3.
| Column-A | Column-B |
| (a) Ignition temperature | (i) The substances which burn in air. |
| (b) Combustion | (ii) Substances having very low ignition temperature. |
| (c) Inflammable substances | (iii) The lowest temperature at which a combustible substance catches fire. |
Answer
| Column-A | Column-B |
| (a) Ignition temperature | (iii) The lowest temperature at which a combustible substance catches fire. |
| (b) Combustion | (i) The substances which burn in air. |
| (c) Inflammable substances | (ii) Substances having very low ignition temperature. |
State whether the following statements are True or False:
Question 1.
Unburnt carbon particles in air are dangerous pollutants causing respiratory problems.
Answer
True
Question 2.
Decreased percentage of carbon dioxide in air has been linked to global warming.
Answer
False
Question 3.
Water can be used to control fires involving electric equipment or oils.
Answer
False
Question 4.
LPG is a better domestic fuel than wood.
Answer
True
Question 5.
In the sun heat and light are produced by nuclear reactions.
Answer
True
Question 6.
Coal is not a fossil fuel.
Answer
False
Question 7.
Wildlife and minerals are exhaustible natural resources.
Answer
True
Question 8.
Coal mainly contains hydrogen.
Answer
False
Question 9.
Petroleum is a dark oily liquid.
Answer
True
Question 10.
CNG is Compressed Natural Gas.
Answer
True
Question 11.
LPG has more calorific value than wood.
Answer
True
Question 12.
A goldsmith use the middle zone of a flame for melting gold, and silver.
Answer
False
Question 13.
The hottest zone of the flame is outermost zone.
Answer
True
Question 14.
A piece of charcoal burns in air and produces carbon monoxide.
Answer
False
Question 15.
The ignition temperature of wood is lower than that of kerosene oil.
Answer
False
Fill in the blanks:
Question 1.
Burning of wood and coal causes …………………… of air.
Answer
pollution
Question 2.
The unit of calorific value of a fuel is ……………………
Answer
kilojoules/kilogram
Question 3.
Cement is a …………………… substance.
Answer
non-combustible substance
Question 4.
The slow process of conversion of dead vegetation into coal is called ……………………
Answer
carbonisation
Question 5.
…………………… is a tough, porous and black substance.
Answer
Coke
Question 6.
A combustible substance cannot catch fire or bum as long as its temperature is lower than its …………………… temperature.
Answer
ignition
Question 7.
The three essential requirements for producing fire are ……………………, …………………… and ……………………
Answer
fuel, air, heat
Question 8.
LPG is …………………… …………………… ……………………
Answer
Liquefied Petroleum Gas
Question 9.
Process of separation of different constituents from petroleum is called …………………….
Answer
refining
Question 10.
…………………… is the rise in temperature of the environment of the earth.
Answer
Global warming
Question 11.
A liquid fuel, used in homes is ……………………
Answer
kerosene
Question 12.
Fuel must be heated to its …………………… before it starts burning.
Answer
ignition temperature
Question 13.
Fire produced by oil cannot be controlled by ……………………
Answer
water
Question 14.
Fuels are stores of energy which of burning give …………………… and …………………….
Answer
heat and light
Question 15.
The colour of outermost zone is ……………………
Answer
blue
Question 16.
The colour of innermost zone of the flame is …………………….
Answer
dark
Question 17.
Fire brigade uses …………………… to extinguish the fire.
Answer
water
Question 18.
Incomplete combustion of a fuel gives poisonous …………………… gas.
Answer
carbon monoxide
Question 19.
Inflammable substances have very …………………… ignition temperature.
Answer
low
Question 20.
The substances which burn in air are called ……………………
Answer
combustible
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