Which of the following functional groups are correctly classified as exerting a purely electron-with — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Groups exerting a $-M$ effect pull electron density away from the conjugated $\pi$ system. These groups typically feature multiple bonds to highly electronegative atoms (like $-NO_2$, $-C\equiv N$, $-C=O$). The methoxy group ($-OCH_3$) possesses lone pairs on the oxygen atom, allowing it to act as an electron donor ($+M$ effect).