Question

Which of the following is not a fossil fuel?
(a) Coal
(b) Alcohol
(c) Natural gas
(d) Petroleum gas

Answer 1

Hint: In this question use the basic definition of a fossil fuel that is generally formed by anaerobic decomposition of buried dead remains over large years. Clearly natural gas, petroleum and coal are naturally obtained via the same process however production of alcohol is somehow artificial and is composed of mixtures of man-made chemicals. This will help approaching the problem.

Complete step-by-step answer:

Fossil fuels:

A fossil fuel is a fuel produced through natural processes, such as anaerobic decomposition of buried dead organisms, comprising organic molecules derived from ancient photosynthesis that release energy through combustion. These organisms and their resulting fossil fuels usually have millions of years of age, and often over 650 million years of age. Peat is often known as a fossil fuel, too. Commonly used fossil-fuel derivatives include kerosene and propane.

Importance of fossil fuels

Fossil fuels are of great significance because they are burnable (oxidized to carbon dioxide and water), providing large quantities of energy per unit mass. Recorded history predates the use of coal as a fuel. Coal had been used to operate furnaces to smelt metal ore. Although in ancient times semi-solid hydrocarbons from seeps were also burnt, they were mainly used for waterproofing and embalming.

Examples of fossil fuels are coal, natural gas, petroleum gas etc.

On the other hand alcohol is the compound of mixtures like carbon, hydrogen and oxygen that does not naturally occur in the environment this is produced by some chemical reactions.

The chemical formula of ethyl alcohol is ${C_2}{H_5}OH$.
Alcohol is also flammable but it is not treated as a fossil fuel.

So this is the required answer.
Hence option (B) is the correct answer.

Note: Fossil fuels are somewhat extinctable as their excess usage can even lead to their depletion however it is not the case with alcohol. Although natural gas like CNG is in abundance and thus it is readily used as a new source of fuel replacing petroleum. Coal is generally found in coal mines, as these fossil fuels are available at some specific locations only and thus their presence in a region make the region resourceful.