Question

Classify the following changes as chemical and physical change:

Rusting of almirah

Answer 1

Chemical change: A change in which one or more new substances are formed and there is a change in the chemical composition of the substance undergoing the change.

Physical change: A change in which no new substance is formed and there is no change in the chemical composition of the substance undergoing the change.

Rusting of almirah is a chemical change.

• Corrosion in case of Iron $\left(\mathrm{Fe}\right)$ is known as rusting.

Corrosion: The process of conversion of metals into their more stable compounds such as metal oxides, metal sulphides or metal hydroxides, etc is known as corrosion.

• Rusting of almirah is a chemical change because a new substance i.e.; Rust or hydrated Ferric oxide$({\mathrm{Fe}}_2{\mathrm{O}}_3.{\mathrm{xH}}_2\mathrm{O})$, a reddish brown flaky substance with a new composition and chemical properties is formed in comparison to the starting material i.e.; almirah made of Iron.