Question

Which type of isomerism is shown by diethyl ether and methyl propyl ether?
A. Chain
B. Functional
C. Metamerism
D. Position

Answer 1

Methyl propyl ether and diethyl ether are indeed isomers of each other. There are actually two isomers of methyl propyl ether, which are methyl n-propyl ether and isopropyl methyl ether. We therefore have three isomers of diethyl ether, all of them ethers. There may be non-ether isomers, particularly n-butanol and 2-methylpropanol, along with their isomers.

Complete step by step answer:
We are given to find which type of isomerism is shown by diethyl ether and methyl propyl ether.
The chemical formula of Diethyl ether is $C{H_3}C{H_2} - O - C{H_2}C{H_3}$.
The chemical formula of Methyl Propyl ether is $C{H_3} - O - C{H_2}C{H_2}C{H_3}$.
After considering the arrangement of two ethyl groups ($- C{H_2}C{H_3}$) around one oxygen atom in diethyl ether and methyl ($C{H_3} -$), propyl ($- C{H_2}C{H_2}C{H_3}$) groups around one oxygen atom in Methyl Propyl ether, these compounds are considered as Metamers.
Metamerism is an outdated term for isomerism. It was originally used to apply to compounds that had the same ratios of atoms (same formulas), but in different arrangements. Metamers are the compounds with the same molecular formula but different number of alkyl groups on either side of the functional group. In metamers, the functional group must be the same, here it is the ketone group.

Hence, the option C is the correct answer.

Note: These two ether molecules have the same number of atoms (four carbon, one oxygen, and ten hydrogen atoms), and thus could be considered 'metamers' in the old terminology. Now, these molecules are considered to be 'constitutional isomers', since they differ in the position of the oxygen atom and branching of the carbon fragments.