Question

Which of the following is used as clean fuel?
A.Leaded petrol
B.Wood
C.Coal
D.Ethanol

Answer 1

Almost all the types of fuels that we use today tend to produce various by – products while undergoing combustion. These by – products are most of the time undesirable and are often harmful for the environment.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
Let us further discuss the products formed by the fuels given to us in the options.
A.Leaded petrol: Leaded petrol is formed by adding tetraethyl lead to gasoline or petrol. This was previously done to improve the performance of petrol engines. There is a condition in engines which is known as ‘knocking’. Knocking causes the mechanical wear and tear of the engine as well reduces the performance of the engine. Leaded petrol did a good job of reducing these problems. But the exhaust gases from these engines brough the general public in direct contact with Lead. Lead is a very toxic metal and can cause fatal health conditions like cancer.
B.Wood: When wood is burnt, the primary by – products formed are carbon dioxide and water. But along with this, some toxic compounds are also released. The most important toxic product formed by the burning of wood is carbon monoxide. Inhalation of carbon monoxide gas for some time can cause the depletion of oxygen levels in the body and cause choking and or may even lead to death.
C.Coal: Coal is by far the most polluting fuels we have discussed so far. The major compounds found when coal is burnt are carbon dioxide, sulphur dioxide, nitrogen dioxide, etc. some of the other carcinogenic effluents include ash, some heavy metals, volatile organic compound, etc.
D.Ethanol: Ethanol is a pure hydrocarbon. So, the combustion of pure ethanol would only give carbon dioxide and water.
Hence, Ethanol can be used as a clean fuel.

Hence, Option D is the correct option

Note: Alcohol stove fuel comes in two principal types: ethanol and methanol. Denatured alcohol (methylated spirits) is ethanol that has been rendered undrinkable (and thus exempt from alcohol taxes) through the addition of methanol and other chemicals.