Which of the following best explains why ethanol is considered a cleaner fuel compared to petrol in automobiles?
Ethanol produces less harmful emissions during combustion
Ethanol (C₂H₅OH) already contains oxygen in its molecule, so it burns more completely than petrol.
More complete combustion means less carbon monoxide, unburnt hydrocarbons and soot; ethanol also has almost no sulphur, so it gives very little sulphur dioxide. This is why it is called a cleaner fuel and is blended with petrol.
Ethanol actually has a lower energy content per gram than petrol, so higher energy is not the reason.
Corrosion of engine parts is a drawback of ethanol, not a reason it is cleaner.
Difficulty in storage and transport is also a practical disadvantage and has nothing to do with emissions.
Hence, the answer is Ethanol produces less harmful emissions during combustion.
Important Questions from Sources of Energy
It is possible to produce algae based biofuels, but what is/are the likely limitation(s) of developing countries in promoting this industry?
1. Production of algae based biofuels is possible in seas only and not on continents.
2. Setting up and engineering the algae based biofuel production requires high level of expertise/technology until the construction is completed.
3. Economically viable production necessitates the setting up of large scale facilities which may raise ecological and social concerns.
Select the correct answer using the code given below:
With reference to two non-conventional energy sources called ‘coalbed methane’ and ‘shale gas’, consider the following ‘statements:
(1) Coalbed methane is the pure methane gas extracted from coal seams, while shale gas is a mixture of propane and butane only that can be extracted from fine-grained sedimentary rocks.
(2) In India abundant coalbed methane sources exist, but so far no shale gas sources have been found.
Which of the statements given above is/are correct?
- What is the typical range of wind speed (in m/s) required for the efficient operation of most commercial wind turbines?
Which of the following is the cleanest source of energy?
Which one of the following is a non-conventional source of energy?
