Answer : The correct option is, (D)
Explanation :
Option A reaction :
It is a combustion reaction. A reaction in which a hydrocarbon react with the oxygen to give product as carbon dioxide and water.
Option B reaction :
It is a combination reaction. A reaction in which the two or more reactants react to give a product.
Option C reaction :
It is a decomposition reaction. A reaction in which a reactant decomposes to form two or more products.
Option D reaction :
It is a single displacement reaction. It is a reaction in which the more reactive element displace the less reactive element. In this reaction, most reactive element chlorine displaces the less reactive element bromine.
Hence, the correct option is, (D)
Well you want the answer with the same letter in it. A.k.a 2. This means they have the same element in them
O2 (Diatomic oxygen that we breathe) and O3 (Ozone that would be deadly to breathe) have different structures.
So the answer is 2