7 Difference Between Substitution Reaction And Addition Reaction With Example

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What Is Substitution Reaction?

A substitution reaction is also referred to as a single displacement reaction, single substitution reaction or single replacement reaction.

Substitution reaction can be described as a reaction in which the functional group of one chemical compound is substituted by another group or it is a reaction which involves the replacement of one atom or a molecule of a compound with another molecule or atom.

Types Of Substitution Reaction

There are two types of substitution reactions that is:

  • Nucleophilic reaction
  • Electrophilic reaction

Example of substitution reaction

The reaction of Ethanol with the hydrogen iodide forms iodoethane along with water.

CH3CH2OH + HI―> CH3CH2OI + H2O

Another example is when CH3Cl reacted with a hydroxy ion (OH-) will produce CH3OH and chlorine. This substitution reaction replaces the chlorine atom on the original molecule with the hydroxyl ion.

CH3Cl + (-OH) ―> CH3OH(methanol) + Cl-

This substitution reaction replaces the chlorine atom on the original molecule with the hydroxyl ion.

Conditions For Substitution Reaction

  • The reaction works well at low temperatures such room temperature
  • Strong bases need to  be in diluted form to avoid chances of dehydrogenation from happening
  • The solution needs to be in molten state.

What You Need To Know About Substitution Reaction

  • A type of reaction in which one atom of any other element substitutes or replaces one of the hydrogen atoms of a given hydrocarbon.
  • It is a characteristic property of saturated hydrocarbons.
  • Example of substitution reaction is Halogenation of alkanes.
  • Gives a product with a slightly changed molar mass.
  • A by-product forms in substitution reaction. The by-product is the leaving group.
  • There is no conversion of a saturated compound into unsaturated compound.
  • The part of the molecule excluding the electrophile or the leaving group is referred to as substrate.

What Is Addition Reaction?

Addition reaction is any of a class of chemical reactions in which an atom or group of atoms is added to a molecule. Additional reactions are limited to chemical compounds that have multiple bonds such as molecules with carbon-carbon double bonds (alkenes) or with triple bonds (alkynes) and compounds that have rings, which are also considered points of unsaturation.  

Addition reaction is the reverse of an elimination reaction. For example, the hydration of an alkene to an alcohol is reversed by dehydration.

Types Of Addition Reaction

There are two main types of polar addition reactions:

  • Electrophilic addition
  • Nucleophilic addition

There are also two types non-polar addition reactions:

  • Free-radical addition
  • Cycloadditions

Examples Of Additional Reaction

An example of addition reaction can be illustrated by the hydrochlorination of propene (an alkene). Here is the equation;

CH3CH=CH2 +HCl ―> CH3C+ HCH3 +Cl- ―> CH3CHClCH3

What You Need To Know About Addition Reaction

  • A type of reaction in which two or more molecules combine with each other to form a single substance.
  • A characteristic property of unsaturated hydrocarbons.
  • An example of additional reactionis Hydrogenation of oils.
  • Gives a product with a high molar mass.
  • There are no by-products that form in addition reactions.
  • Addition reaction makes an unsaturated compound into a saturated compound.
  • The large molecule formed after the addition reaction is referred to as the adduct.

Also Read: Difference Between SN1 And SN2 Reactions

Difference Between Addition And Substitution Reaction In Tabular Form

BASIS OF COMPARISON ADDITION REACTION SUBSTITUTION REACTION
Description A type of reaction in which one atom of any other element substitutes or replaces one of the hydrogen atoms of a given hydrocarbon.   A type of reaction in which two or more molecules combine with each other to form a single substance.  
Characteristic Property Of It is a characteristic property of saturated hydrocarbons.   It is characteristic property of unsaturated hydrocarbons.  
Examples Example of substitution reaction is Halogenation of alkanes.   An example of additional reactionis Hydrogenation of oils.  
Product Gives a product with a slightly changed molar mass.   Gives a product with a high molar mass.  
Conversion of Compounds There is no conversion of a saturated compound into unsaturated compound.   Addition reaction makes an unsaturated compound into a saturated compound.  
By-Product A by-product forms in substitution reaction. The by-product is the leaving group.   There are no by-products that form in addition reactions.  
Molecules The part of the molecule excluding the electrophile or the leaving group is referred to as substrate.   The large molecule formed after the addition reaction is referred to as the adduct.