Ethers are classified as simple (symmetrical) or mixed (unsymmetrical). Which of the following pairs contains only mixed ethers?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → \( \ce{CH3OC2H5} \) and \( \ce{C2H5OC6H5} \)
An ether is simple (symmetrical) when the two alkyl or aryl groups on the oxygen atom are the same, and mixed (unsymmetrical) when the two groups are different.
\( \ce{C2H5OC2H5} \) (ethoxyethane) — two ethyl groups, simple.
\( \ce{CH3OCH3} \) (methoxymethane) — two methyl groups, simple.
\( \ce{CH3OC6H5} \) (anisole) — methyl and phenyl groups, mixed.
\( \ce{CH3OC2H5} \) (methoxyethane) — methyl and ethyl groups, mixed.
\( \ce{C2H5OC6H5} \) (ethoxybenzene) — ethyl and phenyl groups, mixed.
Option (4) is the only pair in which both ethers are mixed.
Why the other options are incorrect
Option (1) \( \ce{C2H5OC2H5} \) and \( \ce{CH3OC6H5} \) — Incorrect. The pair contains a simple ether, C2H5OC2H5.
Option (2) \( \ce{CH3OCH3} \) and \( \ce{C2H5OC6H5} \) — Incorrect. The pair contains a simple ether, CH3OCH3.
Option (3) \( \ce{C2H5OC2H5} \) and \( \ce{CH3OCH3} \) — Incorrect. Both ethers in the pair, C2H5OC2H5 and CH3OCH3, are simple.
NCERT (2026-27 edition):
7.1.3 Ethers – “Ethers are classified as simple or symmetrical, if the alkyl or aryl groups attached to the oxygen atom are the same, and mixed or unsymmetrical, if the two groups are different. Diethyl ether, C2H5OC2H5, is a symmetrical ether whereas C2H5OCH3 and C2H5OC6H5 are unsymmetrical ethers.”