Chemistry - STRUCTURAL ISOMERISM Question with Solution | TestHub

Metamerism is a type of structural isomerism where isomers have the same molecular formula but differ in the nature of the alkyl groups attached to the same polyvalent functional group (such as $-\text{O}-$, $-\text{S}-$, $-\text{NH}-$, $-\text{CO}-$).

In option (1), ${\text{CH}}_3{\text{CH}}_2{\text{CH}}_2\text{OH}$ and ${\text{CH}}_3-\text{CH(OH)}-{\text{CH}}_3$ are position isomers because the position of the $-\text{OH}$ group differs.

In option (2), ${\text{CH}}_3{\text{CH}}_2{\text{CH}}_2{\text{CH}}_2{\text{CH}}_3$ and $({\text{CH}}_3{)}_2{\text{CHCH}}_2{\text{CH}}_3$ are chain isomers because the carbon skeleton differs.

In option (3), ${\text{H}}_3\text{C}-\text{CO}-{\text{CH}}_3$ and ${\text{H}}_3\text{C}-{\text{CH}}_2-\text{CHO}$ are functional isomers because they have different functional groups (ketone and aldehyde).

In option (4), ${\text{CH}}_3{\text{OCH}}_2{\text{CH}}_2{\text{CH}}_3$ (methoxypropane) and ${\text{CH}}_3{\text{CH}}_2{\text{OCH}}_2{\text{CH}}_3$ (ethoxyethane) have the same polyvalent functional group ($-\text{O}-$) but different alkyl groups attached to it (methyl and propyl versus two ethyl groups). Thus, they are metamers.

Answer: ${\text{CH}}_3{\text{OCH}}_2{\text{CH}}_2{\text{CH}}_3$ and ${\text{CH}}_3{\text{CH}}_2{\text{OCH}}_2{\text{CH}}_3$