CBSE Questions for Class 8 Chemistry Combustion And Flame Quiz 7 - MCQExams.com

When clothes of a person catch fire, his body is covered with a blanket to __________.
  • stop the supply of oxygen.
  • make him feel comfortable.
  • save him from any injury.
  • hold his body properly.
Which of the following is necessary for combustion?
  • Oxygen
  • Water
  • Light
  • Carbon Dioxide
The substance which undergoes combustion is called ________.
  • fuel
  • non-inflammable
  • combustible
  • Both $$A$$ & $$C$$

The element carbon is combustible and the element oxygen also supports combustion. What can you say about the nature of compound carbon dioxide?  
  • Supporter of combustion
  • May or may not be supporter of combustion
  • Depends on the nature of carbon
  • Depends on the nature of oxygen
If an office building catches fire, then _______________.
  • only the office furniture is the fuel
  • only the gas cylinders in cafeteria is the fuel
  • the whole building is the fuel
  • none of these
A chemical process in which a substance reacts with oxygen to give off heat is called?
  • Ignition
  • Combustion
  • Conduction
  • None of the above
A candle is burning in the can. After some time, the candle is covered with glass. The flame of the candle:
  • brightens
  • becomes low and gets extinguished
  • No effect
  • Depends on the type of glass
The items which can be used to extinguish fire are:
  • air
  • sand
  • blanket
  • Both B and C
Fire can be extinguished using: 
  • carbon dioxide
  • water
  • blanket
  • all of the above
Which of the following statements is true?
  • Water extinguishes a fire in two ways: (1) It brings the temperature of the combustible material below its ignition temperature. (2) The water vapour formed due to the heat of fire cuts the supply of oxygen.
  • Carbon dioxide is highly volatile. So, it immediately vaporises to cut off the supply of air. In the absence of supporter of combustion, fire is extinguished.
  • Both A and B
  • None of the above
If you fix a burning candle on a petri dish, it will continue to burn, but when you put an inverted beaker over it, the flame goes off. Why does this happen?
  • Insufficient nitrogen in the air.
  • The supply of oxygen is cut off.
  • Both A and B
  • None of the above
Fire can be controlled by removing which of the following factor?
  • Fuel
  • Air
  • Heat
  • All of the above
Inflammable substances have_______.
  • low ignition temperature.
  • high ignition temperature.
  • moderate ignition temperature.
  • none of the above
Which of the following is a combustible substance?
  • Wood
  • Charcoal
  • LPG
  • All of the above
Which of the following is not true about combustion?
  • In case of chimney when air does not enters from below, the candle burns freely.
  • In case of chimney candle burns freely when air enters from below the chimney.
  • In case of chimney when air does not enters from below, the flame flickers and produces smoke.
  • In the absence of air candles flame flickers but does not goes off.
Which of the following is the most common fire extinguisher?
  • Foam
  • $$CO_2$$
  • Water
  • Dry powder
Fire produced by oil cannot be controlled by ___________.
  • $$CO_2$$
  • Foam
  • both a and b
  • Water
_____ is any material that can be made to react so that it releases chemical or nuclear energy as heat.
  • Fossil fuel
  • Fuel
  • Oil
  • All of the above
How does $$CO_2$$ control fire?
  • Forms a blanket around fire.
  • Brings down temperature of the fuel.
  • Both A and B.
  • None of above.
What is calorific value?
  • Amount of heat energy produced on complete combustion of 1 kg of fuel.
  • Amount of heat energy produced on complete combustion of 100 kg of fuel.
  • Amount of heat energy consumed on complete combustion of 1 g of fuel.
  • Amount of heat energy consumed on complete combustion of 1 kg of fuel.
_______ is a fuel made by compressing natural gas.
  • LPG
  • CNG
  • Both A and B
  • None of above
_____ is a better domestic fuel than wood.
  • CNG
  • LPG
  • Petrol
  • All of above
When paper is wrapped around an Aluminium pipe ____________.
  • ignition temperature reduces
  • ignition temperature increase
  • no change in ignition temperature
  • the paper and aluminium catches fire very easily
Wood has now been replaced by which fuel as a domestic fuel?
  • LPG
  • CNG
  • Coal
  • None of the above
Combustion of most fuels releases $$CO_2$$ causing:
  • Water pollution
  • Global warming
  • Acid rain
  • All of above
Which of the following is a solid fuel?
  • Kerosene
  • LPG
  • Charcoal
  • Methane
What is an ideal fuel?
  • It has high calorific value.
  • It is cheap.
  • It is readily combustible.
  • All of the above
Which of the following comes close to being an ideal fuel?
  • Kerosene
  • Petrol
  • Biogas
  • Wood
The ignition temperature of an ideal fuel should _____________.
  • Lowest
  • Highest
  • Neither too high nor too low
  • None of the above
Gasoline combusts in the presence of oxygen. Identify whether Combustion is a physical property or chemical property 
  • There is not enough information to tell if this is a physical or chemical property.
  • This is neither a physical nor a chemical property.
  • This is both a physical and chemical property.
  • This is a physical property.
  • This is a chemical property.
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