Question

Which of the following is NOT a chemical change?
(A) Boiling of water
(B) Boiling of egg
(C) Burning of paper
(D) Burning of cloth

Answer 1

Hint: Chemical change is the process that involves a chemical transformation of a substance to another. Most of the chemical reactions are irreversible however some of them are reversible in nature.

Complete step by step solution
Chemical changes occur mainly when a substance combines with another to form a new substance. Most of the chemical reactions occur as a result of chemical reactions where the atoms or molecules rearrange themselves to form different structures thereby having different properties.
Let’s consider each given option
-Boiling of water: While boiling water no new substances are formed. Also, the chemical composition is not affected by this change and it is reversible too. Hence, we can conclude that boiling of water is a physical change
-Boiling of egg: While boiling egg a new substance is formed by changing the chemical composition of the egg. Also, the change occurred is irreversible. Hence, we can conclude that boiling an egg is a chemical change.
-Burning of paper: While burning of paper a new substance like ash is produced by changing the chemical composition of paper. Also, we cannot reproduce paper from ash since the change is irreversible. Hence, we can conclude that burning of paper is a chemical change.
-Burning of cloth: As in the case of burning paper while burning clothes also new substances like ash are produced and we cannot revert the change since it is irreversible. Hence, we can conclude the burning of clothes as a chemical change.
$ \therefore $ Option A is the answer.

Note
As chemical changes are permanent changes undergone by occurring changes in composition of the objects most of them are irreversible. It also results in the formation of new substances during a chemical change.