Question

Consider structures I to VII and answer the question:

I.	CH3 – CH2 – CH2 – CH2 – OH
II.	\[\begin{array}{cc} \ce{CH3 - CH2 - CH - CH3}\\ \phantom{.....}|\\ \phantom{.......}\ce{OH} \end{array}\]
III.	\[\begin{array}{cc} \phantom{...}\ce{CH3}\\ \phantom{}|\\ \ce{CH3 - C - CH3}\\ \phantom{}|\\ \phantom{..}\ce{OH} \end{array}\]
IV.	\[\begin{array}{cc} \ce{CH3 - CH - CH2 - OH}\\ |\phantom{........}\\ \ce{CH3}\phantom{......} \end{array}\]
V.	CH3 – CH2 – O – CH2 – CH3
VI.	CH3 – O – CH2 – CH2 – CH3
VII.	\[\begin{array}{cc} \ce{CH3 - O - CH - CH3}\\ \phantom{...}|\\ \phantom{......}\ce{CH3} \end{array}\]

Identify the pairs of compounds which are functional group isomers.

Answer 1

The compounds with the same molecular formula but different functional groups are said to be functional group isomers. 

Alcohols are found to be the functional isomers of ether. In the given structures, I, II, III, IV alcohol functional group is present and V, VI, VII contains ether functional group. Hence, I and V, I and VI, I and VII, II and V, II and VI, II and VII, III and V, III and VI etc are functional group isomers.