Question

In a reaction involving ring substitution of \(C_6H_5Y\), the major product is the meta-isomer. The group \(Y\) can be:

• A. \(-NH_2\)
• B. \(-COOH\)
• C. \(-CH_3\)
• D. \(-Cl\)

Hint:

Meta-directing groups are strong electron-withdrawing groups such as: \[ -COOH,\; -NO_2,\; -SO_3H,\; -CHO,\; -CN \] Most electron-donating groups are ortho/para directors.

Answer 1

The Correct Option is B

Step 1: Recall directing effects in electrophilic aromatic substitution. Substituents on a benzene ring influence the position of incoming electrophiles:
Ortho/para directors — donate electron density to the ring.
Meta directors — withdraw electron density from the ring.
Step 2: Classify the given substituents.
\(-NH_2\): Strongly electron-donating, ortho/para-directing
\(-CH_3\): Electron-donating (hyperconjugation), ortho/para-directing
\(-Cl\): Deactivating but donates by resonance, ortho/para-directing
\(-COOH\): Strongly electron-withdrawing (\(-I\) and \(-M\) effects), meta-directing
Step 3: Identify the meta-directing group. Only the \(-COOH\) group withdraws electron density from the ring sufficiently to direct substitution predominantly to the meta position.
Hence, the correct answer is \[ \boxed{-COOH} \]