Question

(a) What is meant by a functional group ? Explain with an example.

(b) Write three common functional groups present in organic compounds. Give their

symbols/formulae.

(c) Name the functional groups present in the following compounds :

(i) CH₃COOH (ii) CH₃CH₂CHO (iii) C₂H₅OH (iv) CH₃COCH ₂CH₃

(d) Name the functional group which always occurs in the middle of a carbon chain.

(e) Draw the structures for the following compounds :

(i) Ethanal (ii) Propanal (iii) Butanal (iv) Pentanal

Answer 1

(a) An ‘atom’ or ‘a group of atoms’ which makes a carbon compound (or organic compound) reactive and decides its properties (or functions) is called a functional group. The alcohol group, -OH, present in ethanol, C₂H₅OH, is an example of a functional group.

(b) (i) Halo group: -X

(ii) Alcohol group: -OH

(iii) Aldehyde group: -CHO

(c) (i) Carboxylic acid group

(ii) Aldehyde group

(iii) Alcohol group

(iv) Ketone group

(d) Ketone group, -CO-