Question

Rusting of iron is a physical change.
A. True
B. False

Answer 1

Hint: In nature the matter generally undergoes two types of changes. One is physical change and the other one is chemical change. If the change is going to affect the form of a chemical substance, then it is called physical change and if the chemical composition of the matter is going to change then the change is called chemical change.

Complete answer:
- In the question there is a statement ‘Rusting of iron is a physical change’, we have to find if the statement is true or false.
- Rusting of iron means the iron is undergoing a process to get rust.
- Now we have to identify whether it is chemical change or physical change.
- The chemical equation which is going to explain the process of rusting is as follows.
\[4Fe+2{{O}_{2}}\xrightarrow{Moisture}\underset{Rust}{\mathop{2F{{e}_{2}}{{O}_{3}}.x{{H}_{2}}O}}\,\]
- In the above chemical equation 4 moles of iron are going to react with 2 moles of oxygen in the presence of water (moisture) and form rust (Ferric oxide) as the product.
- Means Iron (II) is going to convert into Iron (III) in the presence of the moisture.
- Means we can see the change of chemical composition of the iron in the process of rusting, so rusting is chemical change.

Therefore, the correct option is B.

Note:
Sometimes the corrosion or rusting is going to occur in the presence of the acids. Then the process is called acidic corrosion. The process of rusting can be prevented by coating the iron surface with paints.