Question

Which of the following group(s) is/are $m$-directing?

• A. $-Cl$
• B. $Ph-CH=C{H}_2$
• C. $-CHO$
• D. $-COOH$

Answer 1

Answer: (C), (D)

Although halogens are deactivating by -Ieffect, they are $o$ - and $p$-directing due to $+R$ effect. $Ph-$ $CH=C{H}_2$ due to electromeric effect, donates $\pi e^{-}$s to the benzene and stabilizes intermediate $\sigma$ -

Also, $(-CHO)$ and $(-COOH)$ do not have LP ${\bar{e}}^{\prime }$ s and thus withdraw ${\bar{e}}^{\prime }$ s from benzene ring and deactivate the ring at $o$ - and $p$-position. Thus, they are $m$ directing