Combustion and flame
1. While cooking, if the bottom of the vessel is getting black on the outside, it
means that
(a) The food is not cooked completely
(b) The fuel is not burning completely
(c) The fuel has high calorific value
(d) The fuel is burning completely.
2. The hottest zone in the candle flame is the
(a) Non-luminous zone
(b) Luminous zone
(c) Invisible zone
(d) all zones are equally hot.
3.LPG burns with a
(a) non-luminous flame
(b) luminous flame
(c) yellow flame
(d) both (a) and (b).
4.The salt used in soda acid type extinguisher is
(a) potassium carbonate
(b) sodium nitrate
(c) sodium bicarbonate
(d) potassium nitrate.
5.Burning of charcoal in a closed room will produce
a) carbon dioxide
(b) carbon monoxide
(c)nitrogen dioxide
(d) sulphur dioxide.
6.The zone that produces yellow light in the candle flame is
(a) non-luminous zone
(b) luminous zone
(c) invisible zone
(d) all zones give light.
7.Coal burns with
(a) flame
(b) only glow
(c) both flame and glow
(d) does not burn.
8.Combustion is a
(a) physical process
(b) chemical process
(c) both (a) and (b)
(d) None of these.
9. In presence of water, ignition temperature of paper
(a) Decreases
(b) Increases
(c) remains constant
(d) can decrease or increase
10. Use of which fuel in the vehicles has reduced pollution?
(a) Petrol. (b) Diesel. c) CNG (d) Kerosene.
11.Place a piece of burning charcoal on an iron plate and cover it with a
plastic jar. The charcoal stops burning because
(a) its ignition temperature is lowered
(b) supply of oxygen is cut off
(c) it becomes cold after some time
(d) none of the above.
12. Ideal fuel has calorific value.
(a) low
(b) moderate
(c)high
(d) zero
13. Which element shows spontaneous combustion?
(a) Calcium
(b) Copper
(c) Phosphorus
(d) Iron
14. In the sun, heat and light are produced by
(a) chemical reaction
(b) nuclear reaction
(c) ionic reaction
(d) reduction reaction.
15. Which of the following can be used to generate electricity?
(a) Glass
(b) Wind
(c) Soil
(d) Stone
16. Mark the correct statement.
(a) Biogas is obtained from plant and animal wastes.
(b) Biogas pollutes the air while wood does not.
(c) Using biogas is more expensive than wood.
(d) Water should be used for oil or petrol fires.
17. The central zone of the candle flame is luminous due to
(a) incomplete combustion of wax vapours
(b) complete combustion of wax vapours
(c) no combustion of wax vapours
(d) formation of carbon dioxide.
18.Respiration is a reaction which can be called
(a) combustion
(b) substitution
(c) polymerisation
(d) carbonisation.
19.Which of the following is fuel for our body?
(a) Petrol
(e) Food
(b) Diesel
(d) Water
20. Digestion of food is in an example of
(a) incomplete combustion
(b) complete combustion
(c) slow combustion
(d) rapid combustion.
21. Which of the following oxides are present in acid rain?
(a) Phosphorus oxides
(b) Sulphur oxides
(c) Nitrogen oxides
(d) Both (b) and (c).
22. Which of the following phenomenon is responsible for global warming?
(a) Greenhouse effect
(b) Acid rain
(c) Ozone formation
(d) None of these
23. We can prevent energy crisis if we
(a) use non-renewable sources of energy
(b) slow down the use of fuels like coal and petroleum
(c) start using sources like wind, sunlight,hydro energy, etc.
(d) both (b) and (c).
24. A good fuel
(a) should have low calorific value
(b) should cause pollution
(c) should have high ignition temperature
(d) should be easy to transport.
25. Which of the following has lower ignition temperature?
(a) Wood
(b) Paper
(c) Vegetable oil
(d) Kerosene oil
26. Fire extinguishers extinguish the fire by
(a) cutting off the supply of air
(b) bringing down the temperature of fuel
(c) supplying air to the fuel
(d) both (a) and (b).
27. Unburnt carbon particles of the fuel cause
(a) stomach infections
(b) respiratory problems
(c) brain infections
(d) skin problems.
28. Why do we use paper or kerosene oil to start fire in wood or coal?
(a) To reach the ignition temperature of wood or coal by burning of paper or
kerosene.
(b) To supply more oxygen through kerosene.
(c) To give blue flame to the wood or coal.
(d) For spreading the fire.
29. Why do fire brigades pour water on the fire?
(a) Water cools the combustible material so that its temperature is brought
below its ignition temperature.
(b) This prevents the fire from spreading.
(c) Water vapours help in cutting off the supply of air.
(d) All of the above.
30. Flames of the mixture are used for welding.
(a) oxyhydrogen
(b) oxynitrogen
(c) oxycarbon
(d) oxymethane
31.Hydrogen satisfies the conditions of an ideal fuel but cannot be used
freely because
(i) it has high ealorific value.
(ii) it is difficult to store and transport.
(iii) it is soluble in water.
(iv) it is highly inflammable.
Select the correct statements.
(a) (i) and (iii)
(b) (i) and (ii)
(e) (ii) and (iv)
(d) (iii) and (iv)
32. The hottest part of the Bunsen burner is
(a) yellow zone
(b) zone of complete combustion
(c) zone of partial combustion
(d) all parts of the flame are equally hot.
33. Read the following statements.
1. Water is the best extinguisher for fires involving inflammable materials
2. Carbon dioxide is used to extinguish fires involving oil and petrol
3. Water is not suitable for fires involving electrical equipments.
4. Fires caused by short-circuit should be immediately put off by sprinkling
water on it.
Which alternative has the correct statements.
(a) 2 and 3
(b) 3 and 4
(c) 1 and 2
(d) 2 and 4
34. The formation of soot occurs when
(a) there is not enough oxygen for burning and few carbon particles are left
unburnt
(b) there is enough oxygen for burning carbon particles
(c) there is not enough oxygen for burning hydrogen
(d) none of these.
35. The necessary conditions for combustion process to occur are
1. Availability of air/oxygen only
2. Availability of air/oxygen and fuel
3. Temperature of fuel below ignition temperature
4. Temperature of fuel above ignition temperature
Select the correct alternative.
(a) 1 and 2
(b)2 and 4
(c) 3 and 1
(d) 4 and 1
36.Students were carrying out an experiment in the laboratory, in which one
of the steps involved heating the alcohol. However, the teacher strictly
instructed the students not to heat alcohol directly on flame. Why do you
think the teacher gave such an instruction?
(a) The temperature of the flame is not high enough to heat alcohol.
(b) Alcohol is highly inflammable.
(c) The heat of the flame is sufficient enough to overcome the ignition
temperature of alcohol and it can easily catch fire.
(d) Both (b) and
37.When the matchstick strikes against the rubbing surface, what happens
to the red phosphorus?
(a) It converts into white phosphorus.
(b) It reacts with potassium chlorate.
(c) It ignites antimony trisulphide.
(d) No reaction takes place.
38. Which statement best explains the spontaneous combustion?
(a) It is the ability of materials to burn with the help of some source of heat
like flame or spark.
(b) It is the ability of certain materials to start burning without any flame,
spark, heat or ignition source.
(c) It is the ability of certain materials to remain unburnt.
(d) It is the ability of certain materials to burn without oxygen.
39.State which of the following statements is false.
(a) The matter contained in the body of plants and animals is called biomass.
(b) Biogas is produced by decay of biomass.
(c) Petroleum is formed from the remains of dead animals in the sea.
(d) Fossil fuels should be conserved because they give lot of energy.
40.Identify the correct statements.
(i) Carbon dioxide is used to extinguish fires involving oil and petrol.
(ii) Sand is used for extinguishing fires caused by oil.
(iii) Fires caused by short-circuit should not be put off by sprinkling water on
it.
(iv) Water is not the best extinguisher for fires involving petrol and kerosene.
(a) (i), (ii) and (iii)
(b) (ii) and (iii)
(c) (ii) and (iv)
(d) All of these
41.The upper most part of match stick is made up of
(a) antimony trisulphide and potassium chlorate
(b) antimony trisulphide and potassium perchlorate
(c) red phosphorus and white phosphorus
(d) antimony trisulphite and potassium perchlorate.
42.- Which of the following statements are true?
I. In the luminous zone of candle flame, vaporised wax gets oxidised to
carbon dioxide which burns with a blue flame.
II. There is no burning in the dark inner zone of the flame.
III. Non luminous zone is the hottest part of the flame.
IV. Luminous zone of a flame is mainly due to incomplete burning of carbon.
(a) I and III only
(b) II and III only
(c) II, III and IV only
(d) All of these
43.Water is not a suitable fire extinguisher to douse the fires involving oil
and petrol because
(a) water may conduct electricity
(b) water is heavier than oil
(c) water cannot be stored at high pressure in cylinders
(d) water is lighter than oil.
44.If Raman opened the air-hole of a bunsen burner fully and lighted the
burner, he will get.
(a) A luminous flame which is orange-yellow in colour.
(b) A non-luminous flame which is pale blue in colour.
(c) A flame that strikes back which is thin blue or green-yellow in colour.
(d) A smoky flame which gives off a lot of soot.
45. Wax burns with a flame because
(a) liquid wax is vaporised and the vapours of wax burn
(b) carbon from the wax vaporises to burn
(c) carbon from the wax combines with oxygen to form carbon dioxide which
burns
(d) hydrogen of the wax burns to form water.
46.Read the given statements carefully.
P: I am the most common fire extinguisher but not suitable for oil, petrol and
electrical fires. I am heavier than oil and also, conduct electricity.
Q: I am an excellent fire extinguisher and most suitable for oil, petrol and
electrical fires. I also, form a blanket around the fire and bring down the
temperature of the fuel.
Identify P and Q.
(a) P - C*O_{2} Q - H₂O
(b) P - H_{2}*O Q - CO
(c) P - O_{2} Q - C*O_{2}
(d) P - H_{2}*O Q - C*O_{2}
47.Mr. Verma while watching TV suddenly came across an accident as shown
below.
In the above situation, what should Mr. Verma do?
(a) He should pour water on the fire.
(b) He should use oil to cut off the supply of air.
(c) He should use CO2 extinguisher on fire.
(d) He should use LPG to control fire.
48. Match the column I with column II and select the correct option from the
codes given below.
Column I
Column II
(a) Hottest zone of candle flame
(i) Zone of unburnt wax vapours
(b) Yellow zone of candle flame
(ii) Non-luminous zone
(c) Black innermost zone of the candle flame
(iii) Incomplete combustion zone
(a) (a)-(i), (b)-(ii), (c)-(iii)
(b) (a)-(ii), (b)-(i), (c)-(iii)
(c) (a)-(i), (b)-(iii), (c)-(ii)
(d) (a)-(ii), (b)-(iii), (c)-(i)
Multiple choice questions
49.Organic compounds will always contain
(1) carbon
(3) nitrogen
(2) hydrogen
(4) sulphur
50. Which of the following is an Isotope of carbon?
(1) C-12
(3) C-13
(2) C-14
(4) All of these
51. Organic compounds are generally
(1) covalent in nature
(2) ionic in nature
(3) insoluble in organic solvents
(4) soluble in water
52. Covalent compounds
(1) have high melting and boiling points than lonic compounds.
(2) are mostly soluble in water.
(3) are formed between atoms of metals and nonmetals
(4) are formed by the sharing of electrons in the bonding atoms.
53. Which is not the allotrope of carbon?
(1) Diamond (3) Methane
(2) Graphite (4) Fullerene
54. Which of the following is the purest form of carbon?
(1) Charcoal. (2) Coal
(3) Lamp Black. 4) Diamond
55.. Diamond is a
(1) crystalline solid (3) both(1) and (2)
(2) amorphous solid (4) none of these
56. Petrol, diesel and oil are the examples of sources of energy while biogas,
wind and sunlight are sources of energy.
Fill in the blanks by choosing the correct option with correct words.
(1) non-renewable, renewable
(2) renewable, non-renewable
(3) renewable, renewable
(4) non-renewable, exhaustible
57.Which of the following is a good conductor of electricity?
(1) Diamond
(2) Both (1) and (2)
(3) Graphite
(4) None of these
58.Which is used in making pencil lead?
(1) Diamond
(2) Coal
(3) Graphite
(4) Fullerene
59. Graphite is used
(1) as a lubricant
(2) in pencil lead
(3) for purification of water
(4) both (1) and (2)
60. Which of the following is a crystalline form of carbon?
(1) Charcoal
(2) Coal
(3) Graphite
(4) Lamp black
61. Buckminster fullerene is an allotropic form of
(1) nitrogen
(2) sulphur
(3) carbon
(4) tin
62. Percentage of carbon present in an air dried sample of Anthracite is
(1) 94-98%
(2) 27 - 30%
(3) 78-86%
(4) 27%
63. Which of the following coals has the highest carbon content?
(1) Lignite
(2) Anthracite
(3) Bituminous
(4) Peat
64. Which of the following is not obtained in the destructive distillation of
coal?
(1) Coal gas
(2) Coal tar
(3) Coke
(4) Nitrogen
65.Which of the following products obtained by destructive distillation of
coal, is not properly matched?
hansi in combustion 104-Theary
(1) Coal tar - Dyes, explosives, paints
(2) Coal gas Fuel
(3) Coke Drinking purposes)
(4) Ammoniacal liquor - Fertilizers
66. has the lowest percentage of carbon.
(1) Lignite
(2) Bituminous
(3) Anthracite
(4) Peat
67. is the common variety of coal used in household.
(1) Anthracite
(2) Bituminous
(3) Peat
(4) Lignite
68.Purest form of coal is
(1) coke
(2) wood charcoal
(3) coal gas
(4) all of these
69. Which of the following is not the crystalline allotropic form of carbon?
(1) Diamond
(2) Graphite
(3) Fullerene
(4) Coke
70. Which of the following has the characteristics of a good fuel?
(1) Coke
(2) Butane
(3) Coal
(4) Kerosene
71.. A correct statement about charcoal, diamond, graphite and methane is
that they all
(1) are allotropes of carbon
(2) are soluble in water
(3) form CO2 on combustion
(4) have high melting points
72. Which of the following names represents the foul smelling, black, thick,
viscous liquid obtained from destructive distillation of coal?
(1) Coke
(2) Coal tar
(3) Coal gas
(4) None of these
73. Ammoniacal liquor is
(1) ammonia absorbed in water
(2) ammonium hydroxide
(3) aqueous solution of ammonia
(4) all of these
74.Animal charcoal, wood charcoal, lamp black and sugar charcoal are
amorphous forms of carbon. Which of the following contains calcium
phosphate?
(1) Animal charcoal
(2) Wood charcoal
(3) Lamp black
(4) Sugar charcoal
75. Charcoal is used
(1) as a fuel
(2) in the purification of water
(3) as a reducing agent
(4) all of these
76. Animal charcoal contains the percentage of carbon
(1) 10
(2) 25
(3) 30
(4) 60
77.Carbon black contains carbon. percentage of
(1) 92
(2) 99
(3) 90
(4) 95
78.Amorphous form of carbon is
(1) coke
(2) diamond
(3) graphite
(4) none of these
79.Carbon black is used in
(1) shoe polish
(2) kajal
(3) bags
(4) both (1) and (2)
80.The distillation of crude petroleum to obtain various commercially useful
fractions is called
(1) cracking
(2) hydroforming
(3) refining
(4) mining
81.Which of the following is fossil fuel?
(1) Petroleum
(2) Cow dung
(3) Wood
(4) Dry leaves
82.Which among the following is a dark coloured, viscous, strong smelling
liquid?
(1) Kerosene
(2) Petroleum
(3) Petrol
(4) Alcohol
83.Crude oil is a complex mixture of
(1) solid hydrocarbons
(2) liquid hydrocarbons
(3) gaseous hydrocarbons
(4) all of these
84.Petroleum is commonly called as
(1) black gold
(2) green gold
(3) yellow gold
(4) blue gold
85.What should be the characteristic of a rocket fuel?
(1) Light and compact
(2) High calorific value
(3) Should burn rapidly
(4) All of these
86.Mixture of carbon monoxide and nitrogen is known as
(1) coal gas
(2) producer gas
(3) oil gas
(4) water gas
87.Which of the following gases is essentially a mixture of carbon monoxide
and hydrogen?
(1) Coal gas
(2) Oil gas
(3) Water gas
(4) Producer gas
88.Natural gas is
(1) CO and Na
(2) Methane
(3) CO and H2
(4) Hydrocarbons
