Answer: Option (B) is the correct answer.
Explanation:
A reaction that does not changes the chemical composition of its participating reactants is known as a physical reaction.
For example, melting of ice is a physical reaction.
Whereas a reaction that changes chemical composition of its participating reactants is known as a chemical reaction.
For example, [tex]Mg(s) + 2HCl(aq) \rightarrow MgCl_{2}(aq) + H_{2}[/tex]
Hence, formation of a gas will yield bubbles which indicates that a chemical reaction has taken place. Change in color does not always shows that a chemical change has occurred.
Dispersion of ink into water is not a chemical change.
Therefore, we can conclude that method of testing substances is a sure way to identify a chemical reaction formation of bubbles.
