Question

Some meta-directing substituents in aromatic substitution are given. Which one is most deactivating?

• A. $-C\equiv N$
• B. $-S{O}_{3}H$
• C. $-COOH$
• D. $-N{O}_2$

Answer 1

The correct option is D $-N{O}_2$

The meta-directing substituents $-C\equiv N$, $-S{O}_{3}H$ and $-COOH$ are moderately deactivating

whereas $-N{O}_2$ is strongly deactivating. Hence, it is most deactivating.

Option D is correct.