Addition Reaction

Addition Reaction

What is an Addition Reaction?

In the simplest of terms of organic chemistry, we can say that an addition reaction is a chemical reaction wherein two or more reactants come together to form a larger single product. But only chemical compounds containing multiple bond character can undergo an addition reaction as a double or triple bond is usually broken to form the required single bonds. An addition reaction is essentially a reverse decomposition reaction wherein a decomposition reaction is a reaction where one compounds one or more elements or compounds. Looking at an example of an addition reaction, hydrochlorination of propane (an alkene), for which the equation is

CH3CH = CH2 + HCl → CH3C+HCH3 + Cl → CH3CHClCH3

Types of Addition Reactions

For polar addition reactions there are two classifications, namely:

  1. Electrophilic Addition reactions
  2. Nucleophilic Addition reactions 

For non-polar addition reactions, we have two classifications, namely:

  1. Free radical addition reactions
  2. Cycloadditions reactions

Electrophilic addition: 

An electrophilic addition reaction can be described as an addition reaction in which a reactant with multiple bonds as in a double or triple bond undergoes has its π bond broken and two new σ bonds are formed.

Electrophilic Addition mechanism between Ethene and Bromine

Electrophilic Addition mechanism between Ethene and Bromine

Nucleophilic addition:

A nucleophilic addition reaction is an addition reaction where a chemical compound with an electron-deficient or electrophilic double or triple bond, a π bond, reacts with a nucleophile which is an electron-rich reactant with the disappearance of the double bond and creation of two new single, or σ, bonds.

Nucleophilic addition - Ketone

Nucleophilic addition – Ketone

Practise This Question

In the reaction

HCCH+2AgNO3NH4OH−−−−X+2NH4NO3+2H2O 'X' is