Question

Which of the following species is most stable?

• A.
• B.
• C.
• D.

Answer 1

The correct option is D

$-N{O}_2$ is an electron-withdrawing group which shows $-M$ effect predominantly. $-Cl$ is also an electron-withdrawing group which shows $-I$ effect predominantly. $-OC{H}_3$ is an electron-donating group which shows $+M$ effect predominantly.

The carbocation having the $-OC{H}_3$ group as an substituent on the ring will be most stable because the $-OC{H}_3$ group will stabilize the carbocation most due to its electron-donating nature ($+M$ effect).