Question

The compounds ${C_2}{H_5}O{C_2}{H_5}$ and $C{H_3}OC{H_2}C{H_2}C{H_3}$ are:
A. chain isomers
B. geometrical isomers
C. metamers
D. conformational isomers

Answer 1

Hint: The term “isomer” is used to describe the molecule that has the same molecular formula, but has different arrangement of atoms in space. Metamers are those organic compounds which have the same molecular formula but different alkyl groups present on either side of the functional group.

Complete step by step solution:
In the hint, we defined what is meant by isomers. Now we will see the different types of isomers.
- Chain isomerism occurs due to the possibility of branching in carbon chains.
- Geometrical isomerism or configurational isomerism or cis-trans isomerism arises when the functional group are present on same side of carbon or are on opposite side of the carbon chain.
- Metamerism arises when organic compounds have the same molecular formula but different alkyl groups on either side of the functional group.
- In ${C_2}{H_5}O{C_2}{H_5}$ and $C{H_3}OC{H_2}C{H_2}C{H_3}$, we can see that in diethyl ether we have 2 carbon atoms on the left side of oxygen but in methyl propyl ether we have one carbon atom on the left of oxygen. On the right hand side of oxygen, we have 2 carbon atoms but in methyl propyl ether, we have 3 carbon atoms. So, we can say that above molecules are metamers.
Therefore, option C is correct.

Note:
Do not get confused between chain isomerism and Metamerism. Chain isomers are those isomers which have different atomic arrangements by having differently branched structure. Remember that as the alkyl groups bonded with ether oxygen are different in both the compounds, we cannot say they are geometrical isomers because there is no change in both atoms’ geometry.