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 $$-\mathrm{C}-\mathrm{C}-$$. The IUPAC group suffix of an alkane is – ane.

Example: Methane CH₄

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

Example: butene

3. Alkynes: The functional group presence in the alkyne is $$-\mathrm{C}\equiv \mathrm{C}-$$ (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

$$\begin{array}{c}|\phantom{..........}|\phantom{....}\\ -\mathrm{C}-\mathrm{OH}-\mathrm{C}-\mathrm{OH}\\ |\phantom{..........}|\phantom{....}\end{array}$$

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

$$\begin{array}{c}\phantom{....}\mathrm{O}\\ |\phantom{....}||\phantom{.}\\ -\mathrm{C}-\mathrm{C}-\mathrm{H}\\ |\phantom{......}\end{array}$$

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

Example: Acetone

$$\begin{array}{c}\mathrm{O}\\ |\phantom{....}||\phantom{....}|\\ -\mathrm{C}-\mathrm{C}-\mathrm{C}-\\ |\phantom{.........}|\end{array}$$

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

$$\begin{array}{c}\phantom{..}\mathrm{O}\\ |\phantom{....}||\phantom{...}\\ -\mathrm{C}-\mathrm{C}-\mathrm{OH}\\ |\phantom{........}\end{array}$$

10. Amine: The functional groups present in an amine are $$-\mathrm{NH}{\phantom{A}}_2>\mathrm{NH}>\mathrm{N}-$$ The IUPAC group prefix of an amine is amino – or the suffix is –amine.

Example: Methylamine

$$\begin{array}{c}|\phantom{....}\\ -\mathrm{C}-\stackrel{\bullet \bullet }{\mathrm{N}}-\\ |\phantom{....}|\end{array}$$

11. Ester: The functional group present in an ester is $$-\mathrm{COOR}$$ .

The IUPAC group suffix of an ester is –ate.

Example: Ethyl acetate

$$\begin{array}{c}\phantom{.}|\phantom{........}|\phantom{.......}|\phantom{........}|\\ -\mathrm{C}-\mathrm{O}-\mathrm{C}--\mathrm{C}-\mathrm{O}-\mathrm{C}-\\ \phantom{.}|\phantom{........}|\phantom{.......}|\phantom{........}|\end{array}$$