Question

Assertion: Burning of fossil fuel is a physical process
Reason: When coal is burnt, the chief component, carbon is changed to carbon dioxide. This process cannot be reversed.
A.Both Assertion and Reason are correct and the reason is the correct explanation for an assertion.
B.Both assertion and reason are correct but the reason is not the correct explanation for an assertion.
C.The assertion is correct but the reason is incorrect.
D.An assertion is incorrect but the reason is correct.

Answer 1

There are two types of changes:
Physical changes: These are the changes that result in a change of physical property of the material that is changing. But the chemical properties are not altered during such a process. These changes are often reversible. An example of such a process is the melting of ice, etc.
Chemical change: Changes that alter the chemical property of the substance changing. These changes are irreversible means once the substance has undergone any chemical change it cannot be restored to its original state. For example, oxidation of iron (rusting of iron)

Complete step by step answer:
The burning of fossil fuels results in the change in the chemical composition of the fuel. For instance, the carbon present in it is converted to carbon dioxide or carbon monoxide, sulfur to its oxides, etc.
These changes are not reversible as they altered the chemical composition of the substance.
Thus, the burning of fossil fuel is not a physical change instead it is a chemical change.
When coal (a fossil fuel), its chief component carbon gets converted into carbon dioxide.
Hence, the assertion is wrong but the reason is correct.

Thus, option D is the correct answer.

Note: Fossil fuels are the conventional sources of energy. They include coal, natural gas, petroleum, etc.
They are extracted from the earth through mining, drilling, and other processes.
Remains of plants and animals that were submerged under the earth’s crust get converted into fossil fuels due to high pressure and temperature.
They are a non-renewable source of energy.
Burning fossil fuels causes air pollution and thus scientists are now looking towards other cleaner and greener sources of energy.