Q.The isomerism exhibited by $C_2H_5OC_2H_5$ and $CH_3-O-CH(CH_3)-CH_3$ is :

Diethyl ether and methyl isopropyl ether are isomers arising from different alkyl groups distributed on either side of the same functional group, which is the definition of metamerism.

Both compounds share the molecular formula $C_4H_{10}O$ and both are ethers (same functional group), so this is not functional isomerism (which requires different functional groups). It is also not simple position or chain isomerism of a single carbon skeleton, since the two compounds differ in how the alkyl groups are distributed around the ether oxygen — diethyl ether has two identical ethyl groups, while methyl isopropyl ether has a methyl and an isopropyl group. This specific type …