Question

Which of the following compounds is a functional group isomer of $C_2{H}_{5}OH$, ethanol (ethyl alcohol)?

• A. ethanal, $C{H}_{3}CHO$
• B. acetic acid, $C{H}_{3}COOH$
• C. diethyl ether, $(C_2{H}_5{)}_{2}O$
• D. dimethyl ether, $(C{H}_3{)}_{2}O$

Answer 1

The correct option is D dimethyl ether, $(C{H}_3{)}_{2}O$

Dimethyl ether, $(C{H}_3{)}_{2}O$ is a functional group isomer of $C_2{H}_{5}OH$, ethanol (ethyl alcohol). Both have same molecular formula $C_2{H}_{6}O$ but different functional groups. Ethanal, $C{H}_{3}CHO$ acetic acid, $C{H}_{3}COOH$ and diethyl ether, $(C_2{H}_5{)}_{2}O$ cannot be functional group isomers of $C_2{H}_{5}OH$, ethanol as they have different molecular formulae.

Note: Functional group isomers have same molecular formula but different functional groups.