Question

Which of the following compounds is a functional group isomer of $\left( {{C_2}{H_5}OH} \right)$ , 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, ${\left( {C{H_3}} \right)_2}O$

Answer 1

Hint: isomers are molecules with the same molecular formula but have different arrangement of atoms and molecules. Isomers can be split into broad groups mainly structural isomers and stereoisomers.

Complete step by step answer:
Molecules that have the same molecular formula but different molecular structure. Our question is related to functional isomers (structural isomers that have the same molecular formula but with the atoms connected in different ways and therefore falling into different categories.
Dimethylether ${\left( {C{H_3}} \right)_2}O$ is functional isomer of ethanol $\left( {{C_2}{H_5}{O_4}} \right)$ because it same molecular formula $\left( {{C_6}{H_6}O} \right)$ but both have different functional groups. Ethanol, $\left( {C{H_3}CHO} \right)$ , Acetic acid $\left( {C{H_3}COOH} \right)$ and diethyl ether ${\left( {{C_2}{H_5}} \right)_2}O$ cannot be functional group of $\left( {{C_2}{H_5}OH} \right)$ ethanol as they have different molecular formula.

This option $\left( D \right)$ is correct.

Additional information:
 Ethanol, Acetic acid, Dimethylether and Dimethylether are classes of organic compounds in one which contain carbon and hydrogen. They have different functional group attached to it in ethanol $\left( { - OH} \right)$ is a functional group, in acetic acid $\left( { - COOH} \right)$ is a function ground and in dimethyl ether and diethyl ether they contain ester $\left( { - RCOR} \right)$ functional group. As their functional groups are different they possess different properties physical as well as chemical.
Ethanol is an organic chemical compound. It is a simple alcohol with chemical formula $\left( {{C_2}{H_6}O} \right)$ .
Acetic acid is weak monoprotic acid. In aqueous solution, it has $p{K_a}$ value of 4.76.Its conjugate base is acetate $\left( {C{H_3}CO{O^ - }} \right)$ .
Dimethylether is an organic compound; it is a colorless gas that is a useful precursor to other organic compounds and an aerosol propellant that is currently being demonstrated for use in a variety of fuel applications. It is an isomer of ethanol
Diethyl Ether or simple ether is an organic compound. It is a colorless highly volatile, sweet-smelling flammable liquid.


Note:
Functional group isomers have the same molecular formula but different functional group. Functional group is one which is a group of atoms whose. Identical functional groups tend to have similar properties.