Question

Identify the homologous series among the following:
1. $HCOOH$
2. $C{H}_{3}COOH$
3. $C_2{H}_6$
4. $C_2{H}_{5}COOH$
5. Propanone

• A. 1, 2 and 5 are homologous series
• B. 1, 3 and 4 belong to the same homologous series
• C. 1, 2 and 4 belong to the same homologous series
• D. 1, 2 and 5 belong to the same homologous series

Answer 1

The correct option is C

1, 2 and 4 belong to the same homologous series

A series of compounds in which the same functional group substitutes for hydrogen in a carbon chain is called a homologous series. 1, 2 and 4 have same functional group (-COOH), so they are homologous in nature. The functional group of propanone is ketone, so it is not homologous with 1, 2 and 4. Again $C_2{H}_6$ does not have any functional group, so it is not homologous with 1, 2 and 4.