Question

Burning of coal in air is a:
(A) Physical change
(B) Chemical change
(C) Reversible change
(D) Endothermic reaction

Answer 1

Hint: Burning of coal in air means we are going to expose a large amount of hydrocarbons to air at higher temperature. Coal contains a huge amount of hydrocarbons means carbon and hydrogen.

Complete step by step answer:
* Coal is a non-renewable energy resource, meaning we won’t get coal from nature on a daily basis.
* Coal is a good source for the production of electricity by thermal power plants.
* We know that coal contains a large amount of carbon and hydrogen.
* Whenever we are going to expose large amounts of coal, which means hydrocarbons, to air new substances are going to form such as carbon dioxide and water.
* Also burning coal releases a huge amount of energy, by using that energy thermal power plants are going to prepare electricity from it.
\[Coal(hydrocarbons)\xrightarrow{air}C{{O}_{2}}+{{H}_{2}}O\]

* If a new substance is going to form from the existence substance by air, water or any chemical, that reaction is called a chemical change.
* We are getting carbon dioxide and water from coal when exposed to air means burning of coal in air is chemical change.
* The reaction is permanent means it is an irreversible reaction, it cannot be reversed.
So, the correct option is B.

Note: Don’t be confused with physical and chemical change. Physical change means only the shape of size of the substance is going to change. But in chemical change new substances are going to form different properties compared to initial substances.