Question

Increasing order of electrophilic substitution for following compounds:

• A. IV<I<II<III
• B. III<II<I<IV
• C. I<IV<III<II
• D. II<III<I<IV

Answer 1

Answer: (A)

IV<I<II<III

Answer 2

The correct option is(A): IV<I<II<III.

Electrophilic aromatic substitution, also referred to as E.A.S, is an organic chemical reaction wherein an atom becomes bonded to an existing aromatic system, replacing a hydrogen atom. Several significant and well-known electrophilic aromatic substitution reactions include:

1. Aromatic nitration
2. Aromatic halogenation
3. Aromatic sulfonation
4. Friedel-Crafts acylation
5. Friedel-Crafts alkylation

Within this set of compounds, we can observe the presence of the following functional groups attached to the aromatic system:

(A) Chlorine atom: Exhibits mild deactivating properties, diminishing nucleophilicity due to its electron-withdrawing effect on the aromatic system.

(B) Methoxy group: Acts as an activating group, enhancing nucleophilicity by donating electrons to the aromatic system.

(C) Methyl group: Also behaves as an activating group, boosting nucleophilicity by donating electrons to the aromatic system.

(D) Nitrile group: Displays strong deactivating characteristics, lowering nucleophilicity by withdrawing electrons from the aromatic system.

Therefore the correct option is (A).