Science - Combustion and Pressure
Exam Duration: 45 Mins Total Questions : 30
What are the two main hydrocarbons present in L.P.G.?
- (a)
Butane + propane
- (b)
Butane + isobutane
- (c)
Propane + ethane
- (d)
Methane + ethane
What is the heat produced by burning 1 g of fuel completely known as?
- (a)
Heat capacity
- (b)
Calorific value
- (c)
Vapour density
- (d)
Boiling point
Which of the following has the highest calorific value?
- (a)
Petrol
- (b)
Coke
- (c)
Natural gas
- (d)
Kerosene
Which of the following has the characteristics of a good fuel?
- (a)
Coke
- (b)
Butane
- (c)
Coal
- (d)
Kerosene
What is burning of a substance in the presence of air with the evolution of heat called
- (a)
Distillation
- (b)
Carbonisation
- (c)
Combustion
- (d)
Refining
When methane burns in air, what are the products formed?
- (a)
CO2 + 2H2O + heat
- (b)
CO2 + H2
- (c)
CO + 02
- (d)
CO2+ 02 + heat
What kind of reaction is combustion?
- (a)
Reduction
- (b)
Redox
- (c)
Substitution
- (d)
Oxidation
Which of the following is a combustible substance?
- (a)
Coke
- (b)
Coal
- (c)
Diamond
- (d)
Wood
If the temperature falls below its ignition temperature, then what happens to the burning substance
- (a)
It gets extinguished.
- (b)
It burns brightly.
- (c)
It burns dimly.
- (d)
It burns with smoke
Which of the following is an example of rapid combustion
- (a)
Candle
- (b)
Cracker
- (c)
White phosphorus
- (d)
Sulphur
In which of the following types of combustion are heat, light and sound produced?
- (a)
Rapid
- (b)
Explosive
- (c)
Spontaneous
- (d)
All of the above
Match the entries in Column-I with those in Column-II correctly
- (a)
a-l, b-2, c-3, d-4
- (b)
a-2,b-3,c-4,d-l
- (c)
a-3,b-4,c-2,d-l
- (d)
a-4,b-l,c-2,d-3
What does the blue zone in an L.P.G. flame indicate?
- (a)
Unburnt vapours
- (b)
Partial decomposition
- (c)
Moderately hot
- (d)
Hottest zone of complete combustion
What does natural gas contain?
- (a)
Methane, ethane, propane.
- (b)
Butane, propane and ethane.
- (c)
Pentene, methane and ethylene.
- (d)
Hexane, butane and ethane.
How is synthetic petrol produced?
- (a)
From petroleum
- (b)
From wood
- (c)
From coal
- (d)
From L.P.G
Arrange the following fuels in the increasing order of their calorific value
- (a)
(i),(ii), (iii), (iv)
- (b)
(ii), (iii), (iv) and (i)
- (c)
(ii), (i), (iii) and (iv)
- (d)
(ii), (iii), (i) and (iv)
What is combustion?
- (a)
An exothermic reaction
- (b)
An endothermic reaction
- (c)
A displacement reaction
- (d)
A reduction reaction
Inspite of the danger involved with hydrogen, it is used for some applications. Where is it used?
- (a)
Rocket fuel
- (b)
Oxyhydrogen flame
- (c)
Car fuel
- (d)
All of the above
What ignition temperature does an inflammable substance have
- (a)
More than 100 °C
- (b)
Less than 100 °C
- (c)
More than 200 °C
- (d)
Between 200 °C to 350 °C
What is the disadvantage of incomplete combustion of a fuel?
- (a)
Unburnt carbon gets released.
- (b)
Air gets polluted.
- (c)
Respiratory problems arise.
- (d)
All of the above
Which of the following is the best extinguisher for inflammable materials?
- (a)
Water
- (b)
Sulphur dioxide
- (c)
Carbon dioxide
- (d)
Carbon monoxide
On which of these factors does the flame produced by a fuel depend upon?
- (a)
Calorific value
- (b)
Amount of oxygen
- (c)
The chemical composition of a fuel
- (d)
All of the above
Which of the following statements is NOT true?
- (a)
CO2 is the best fire extinguisher.
- (b)
Global warming can cause acid rain
- (c)
Burning of coal and diesel releases sulphur dioxide gas.
- (d)
L.P.G.has higher calorific value than biogas.
Why is L.P.G,used as domestic fuel, mixed with a strong smelling volatile liquid like mercaptan?
- (a)
For better combustion
- (b)
For good smell/fragrance
- (c)
For detection of gas leakage
- (d)
For higher calorific value
Hydrogen gas has the highest calorific value i.e., 150 kJ kg-1, yet it is not used as a fuel. Why?
- (a)
It is explosive in nature.
- (b)
It causes storage problem.
- (c)
It causes transportation problem.
- (d)
All of the above
When wood is used as a fuel in chullahs, gaps are left in between logs of wood. Why is it done so?
- (a)
To facilitate movement of air
- (b)
To prevent more consumption of wood
- (c)
To control temperature
- (d)
All of these
An electric spark is struck between two electrodes placed near each other, inside a closed tank full of petrol. What will happen?
- (a)
Spontaneous combustion of petrol
- (b)
Explosion
- (c)
Slow combustion of petrol
- (d)
Nothing will happen
One gram of which of these will give out the maximum amount of heat by complete combustion?
- (a)
Wood
- (b)
Coal
- (c)
Diesel
- (d)
Biogas
What are the essential requirements for a fire to start and continue?
- (a)
Only (i) and (ii)
- (b)
Only (ii) and (iii)
- (c)
Only (i) and (iii)
- (d)
(i), (ii) and (iii)
Which of the following statements is NOT true?
- (a)
Spontaneous combustion takes place without any apparent cause.
- (b)
The luminous zone of a flame has high temperature.
- (c)
Carbon dioxide gas causes global warming.
- (d)
The calorific value of a fuel is expressed in kJ / kg -1