Answer: B) It is going through a physical change.
Explanation:
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: Freezing of water
[tex]H_2O(l)\rightleftharpoons H_2O(s)[/tex]
The solid water can be changed to liquid by heating or lowering the pressure.
The chemical make up of water remains same.
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
[tex]Fe\rightarrow Fe^{2+}+2e^-[/tex]
It can not be reversed.
