Question

Rusting of an article made up of iron is called

• A. corrosion and it is a physical as well as chemical change
• B. dissolution and it is a physical change
• C. corrosion and it is a chemical change
• D. dissolution and it is a chemical change

Answer 1

The correct option is C

corrosion and it is a chemical change

1. Physical changes are those in which the physical properties of the substances change. It is reversible and no new product is formed. Example: conversion of water into steam.
2. Chemical changes are irreversible and a new product is formed. Example: Digestion of food.

Explanation for correct option:

(c) Corrosion and it is a chemical change:

1. Corrosion is the deterioration of metal to attain stability by forming the oxides, sulphides or hydroxides.
2. Oxidization of metal occurs by the action of water, air, moisture or a chemical reaction.
3. Brown flaky material is formed on the surface of iron when the iron is exposed to moist air thus it's also a chemical change.

Explanation for incorrect options:

Since rusting of the iron article is also known as corrosion and it's a chemical change thus options (a), (b) and (d) are incorrect.

Hence, option (c) is the correct option.