Question

Which process is an example of a chemical change?

Answer 1

A metal rail rusting in damp weather.

Answer 2

Answer:

The correct answer is :a metal railing rusting in damp weather is an example of a chemical change.

Explanation:

Physical property is defined as the property of a substance which becomes evident during physical changes. Example: Melting point

A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.

Example: Melting of ice

Chemical property is defined as the property of a substance which becomes evident during chemical changes. Example: Reactivity with other substances

A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.

Example: Corrosion of iron called as rusting.  

Rust is ferric oxide $Fe_2O_3$.

$4Fe+3O_2\righatarrow 2Fe_2O_3$

A metal railing rusting in damp weather  is an example of chemical change because composition of an iron rail is changing.

$4Fe+3O_2\rightarrow 2Fe_2O_3$

Where as other examples given are the examples of physical change.