Give various functional isomers of butanoic acid and give their isomeric relations.

Explanation

(1) and (2), (1) and (3), (1) and (4), and (1) and (5) are functional isomers.
(2) and (3), (2) and (4), and (2) and (5) are metamers.
(3) and (4), and (3) and (5) are metamers.
(4) and (5) are position isomers.