What is an addition reaction?
Firstly, an addition reaction is a type of reaction like acid/base, condensation, combustion, or decomposition. All these types of reactions have their own characteristics and their own definitions. So what is it that defines an addition reaction?
Let’s have a look at an example, the bromination of ethene. In this reaction, bromine, Br₂, is added to ethene, forming 1,2-dibromoethane. It’s obvious why this is called a bromination because we’re adding bromine to a chemical. But why is it also an addition reaction?
Let’s have a look at another example. How about the combustion of carbon? Carbon, probably in the form of graphite, is reacted with oxygen, forming carbon dioxide. The question is, what do these two reactions have in common?
First of all, they both involve two reactants and one product. This means there are no byproducts. So an addition reaction is a reaction in which two reactants combine to form a larger molecule without byproducts.
During this question, you may have been thinking of another type of reaction that’s commonly mentioned alongside, the condensation reaction. Condensation reactions are definitely not addition reactions because they produce byproducts, which are usually water or another small molecule. You might find it helpful to remember addition reactions as two reactants combining or adding together and condensation reactions producing condensation, which is water.