Question

Describe the substitution And Addition Reactions as chemical properties of carbon compounds

Answer 1

Addition reactions:

Unsaturated organic compounds, like alkenes and alkynes, contain multiple bonds (C=C, C≡C) between their carbon atoms.They undergo addition reactions to become saturated in nature.

The formation of larger molecules by addition of more radicals is known as addition reaction.During an addition reaction of unsaturated organic compounds, a reagent takes place at the double bonded or a triply bonded carbon atoms.

For example; ethene is converted into ethane when heated with the catalyst nickel.

CH2=CH2 + H2 + (Nickel catalyst) ⇨ CH3−CH3

Nickel acts as a catalyst, which basically regulates (increase/decrease) the rate of a given reaction, without itself undergoing any chemical change.

When ethene undergoes an addition reaction with chlorine, it gives dichloroethane.



Chlorine is a halogen, whose atoms partially break the carbon-carbon double bond in the alkene to a single bond and add itself across it.

Substitution Reaction:

A Substitution reaction is one in which an atom or a group of atoms(functional group)  in the compound are replaced by another atom (or group of atoms). Substitution reactions are single displacement reactions.

Alkanes, which have only single bonds between their carbon atoms, are saturated hydrocarbons.They are chemically least reactive.They are also called paraffin, as they have no affinity (minimum affinity)towards chemical changes (parum=little; affins=affinity).However, under suitable conditions, they undergo substitution reactions.

For example, under the presence of Sunlight, Methane reacts with chlorine gas to produce chloromethane and hydrogen chloride.

CH4 + Cl2 + Sunlight ⇨ CH3Cl + HCl

Sunlight (UV Light) breaks down the chlorine into free radicles, which initiates the substitution reaction.

These reactions define the chemical properties of carbon compounds