Functional Group In Organic Chemistry

Organic chemistry is the analysis of the properties, structure, composition, structure interactions, and processing of carbon-containing substances that include chemical compounds involving hydrogen, oxygen, nitrogen, halogens, silicon, phosphorus and sulphur, among others. It is a branch of chemistry that was once restricted to compounds formed by living organisms, but it has since expanded to include human-made materials, including fabrics and plastics. Organic compounds have a wide variety of applications, including but not limited to medicines, petroleum, food, weapons, cosmetics and paints. 

In organic chemistry, a functional group is a moiety in a compound that causes the molecule’s characteristic chemical processes. Organic chemistry allows for the systematic investigation of chemical reactions, chemical substance behaviour, and chemical synthesis development. Its surroundings can influence the reactivity of a functional group.

Various functional groups

Functional Groups are a group of components that are responsible for the distinct chemical reactions of these molecules. Identical chemical reactions can be carried out by two molecules of different dimensions but with the same functional groups. A functional group’s involvement in a compound indicates that the molecule’s actions and chemical reactions are influenced by it. Some common examples of functional groups are,

  • Hydrocarbons

The hydrocarbon functional groups may have an ionic charge. Carbocations refer to positively charged structures, whereas carbanions refer to negatively charged hydrocarbons. Hydrocarbon functional groups include alkane (single carbon-carbon bond), alkene (double carbon-carbon bond), and alkynes (triple carbon-carbon bond).

Functional groups Nomenclature Examples
Alkanes -ane Methane, ethane, butane
Alkenes -ene Ethene, butene
Alkynes -yne Ethyne, butyne


  • Alcohols

Alcohol functional group wherein the -OH group is attached to a side chain of the organic compound or aliphatic chain.  Alcohols are classified as monohydric (containing just one OH group), dihydric (containing two OH groups), or trihydric (containing three OH groups) depending on the number of hydroxyl groups in the molecule.

Functional groups Nomenclature Examples
Alcohol -ol Methanol, butanol


  • Ethers

Ethers are organic compounds in which the oxygen atom is bound to two alkyl or aryl groups, which may be the same or different. R-O-R, R-O-R’, R-O-Ar, or Ar-O-Ar is the general formula for ether, in which R represents an alkyl group and Ar represents an aryl group.


Functional groups Nomenclature Example
Ethers -oate Ethyl ethanoate


  • Alkyl halides and aryl halides

Alkyl halides are organic compounds with the general formula RX, where R stands for alkyl and X for halogen. The two forms of substituted hydrocarbons are alkyl halides and aryl halides. Haloalkanes and haloarenes are the names for alkyl halides and aryl halides, respectively.


  1. Ethyl chloride (CH3CH2Cl)
  2. Chlorobenzene (C6H5-Cl)


  • Aldehyde and Ketone Groups

Ketones and aldehydes are the compounds that comprise the carbonyl group. Other than in formaldehyde, the carbonyl carbon is attached to at least one hydrogen atom and carbon in the aromatic or aliphatic group in aldehydes. The carbonyl carbon in ketones is bound to two aromatic or aliphatic groups.


Functional groups Nomenclature Example
Aldehydes -al Methanal
Ketones –one Butanone


  • Carboxylic acid

Carboxylic acids are organic compounds that contain the carboxyl functional group. Aliphatic carboxylic acid and Aromatic carboxylic acid are two forms of carboxylic acids.


Functional groups Nomenclature Example
Carboxylic acid -oic acid Butanoic acid


  • Amides

The amide functional group has the formula R-(CO)-NR2, indicating that it contains a carbonyl carbon bonded to a nitrogen atom, which is then bonded to two other alkyl groups. Primary, secondary and tertiary amides are the three categories of amides. The differences are categorized according to the nitrogen atom location in connection to the carbon atom in the chain of a molecule.


Functional groups Nomenclature Example
Amide -amide N-Methylacetamide



Functional groups are atom gatherings within molecules with structural properties independent of the other atoms in the complex. Instances include alcohols, amines, carboxylic acids, ketones, aldehyde and ethers.


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