Question

Explain the following term with an example.

Functional group

Answer 1

Functional group: The functional group is defined as an atom or group of atoms joined in a specific manner, which gives the chemical properties of the organic compound and they are the centers for chemical reactivity. Compounds having a similar functional group have undergoes similar reactions.

For example:

1. Alkane: The functional group presence in the alkane is \[\ce{-C-C -}\]. The IUPAC group suffix of an alkane is – ane.

Example: Methane CH₄

2. Alkene: The functional group presence in the alkene is \[\ce{- C = C -}\] (double bond). The IUPAC group suffix of an alkene is – ene.

Example: butene

3. Alkynes: The functional group presence in the alkyne is \[\ce{- C ≡ C -}\] (triple bond). The IUPAC group suffix of an alkyne is – yne.

4. Arenes: They contain a benzene ring as the functional group. 

Example: Benzene

5. Halides: The functional group presence in halides is X(halogen).

Example: Chloromethane

6. Alcohols: The functional group, which is present in alcohol, is -OH. The IUPAC group suffix of alcohol is – ol.

Example: Ethanol

\[\begin{array}{cc}
|\phantom{..........}|\phantom{....}\\
\ce{- C - OH - C - OH}\\
|\phantom{..........}|\phantom{....}
\end{array}\]

7. Aldehydes: The functional group, which is present in an aldehyde, is \[\ce{- CHO}\]. The IUPAC group suffix of an aldehyde is \[\ce{–al}\].
Example: Formaldehyde

\[\begin{array}{cc}
\phantom{....}\ce{O}\\
|\phantom{....}||\phantom{.}\\
\ce{- C - C - H}\\
|\phantom{......}
\end{array}\]

8. Ketones: The functional group, which is present in a ketone is \[\ce{>C=O}\]. The IUPAC group suffix of a ketone is –one.

Example: Acetone

\[\begin{array}{cc}
\ce{O}\\
|\phantom{....}||\phantom{....}|\\
\ce{- C - C - C -}\\
|\phantom{.........}|
\end{array}\]

9. Carboxylic acid: The functional group present in a carboxylic acid is \[\ce{- COOH}\]. The IUPAC group suffix of a carboxylic acid is – oic acid.
Example: Acetic acid

\[\begin{array}{cc}
\phantom{..}\ce{O}\\
|\phantom{....}||\phantom{...}\\
\ce{- C - C - OH}\\
|\phantom{........}
\end{array}\]

10. Amine: The functional groups present in an amine are \[\ce{- NH2 > NH > N -}\] The IUPAC group prefix of an amine is amino – or the suffix is –amine.

Example: Methylamine

\[\begin{array}{cc}
|\phantom{....}\\
\ce{- C - \overset{\bullet\bullet}{N} -}\\
|\phantom{....}|\end{array}\]

11. Ester: The functional group present in an ester is \[\ce{-COOR}\] .

The IUPAC group suffix of an ester is –ate.

Example: Ethyl acetate

\[\begin{array}{cc}
\phantom{.}|\phantom{........}|\phantom{.......}|\phantom{........}|\\
\ce{- C - O - C -- C - O - C -}\\
\phantom{.}|\phantom{........}|\phantom{.......}|\phantom{........}|\\\end{array}\]