Question

Draw formulas for the first five members of each homologous series beginning with the following compounds. 

(a) H–COOH 

(b) CH₃COCH₃ 

(c) H–CH=CH₂

Answer 1

The first five members of each homologous series beginning with the given compounds are shown as follows: 

(a) 

H–COOH : Methanoic acid 

CH3–COOH : Ethanoic acid 

CH₃–CH₂–COOH : Propanoic acid 

CH₃–CH₂–CH₂–COOH : Butanoic acid 

CH₃–CH₂–CH₂–CH₂–COOH : Pentanoic acid 

(b) 

CH₃COCH₃ : Propanone CH₃COCH₂CH₃ : 

Butanone 

CH₃COCH₂CH₂CH₃ : Pentan-2-one 

CH₃COCH₂CH₂CH₂CH₃ : Hexan-2-one 

CH₃COCH₂CH₂CH₂CH₂CH₃ : Heptan-2-one 

(c) 

H–CH=CH₂ : Ethene 

CH₃–CH=CH₂ : Propene 

CH₃–CH₂–CH=CH₂ : 1-Butene 

CH₃–CH₂–CH₂–CH=CH₂ : 1-Pentene 

CH₃–CH2–CH₂–CH₂–CH=CH₂ : 1-Hexene