JEE Main 2025 · 29 January · morning · Single correct · +4 / −1

In the following substitution reaction :
Product 'P' formed is :

JEE Main PYQ figure
  1. (a)
    Option (a)
  2. (b)
    Option (b)
  3. (c)
    Option (c)
  4. (d)
    Option (d)
Answer and solution

Answer (d)

Solution

Chemistry ma’am · 3 steps

Check where each Br sits relative to NO₂: only the para Br is activated, so only that one leaves.

  1. Read the substrate. The ring carries NO₂ at C1, one Br at C3 and one Br at C4. So one Br is meta to NO₂ and the other is para to it. Ethoxide, C₂H₅O⁻ from C₂H₅ONa, is the nucleophile.
  2. How haloarenes react. A haloarene undergoes nucleophilic substitution only when an electron-withdrawing group sits ortho or para to the halogen. When C₂H₅O⁻ adds to the carbon holding Br, the negative charge of the intermediate spreads onto the carbons ortho and para to that carbon. A NO₂ group on one of those carbons can hold the charge on its oxygen atoms.
    BrominePosition relative to NO₂Can NO₂ hold the negative charge?Substituted?
    Br at C4parayes, the charge reaches C1 and goes onto NO₂yes, replaced by OC₂H₅
    Br at C3metano, the charge never reaches C1no, stays as Br
  3. So. Only the para Br is swapped for OC₂H₅. P is 2-bromo-1-ethoxy-4-nitrobenzene, with OC₂H₅ para to NO₂ and Br next to OC₂H₅. That is option (d).

The idea to keep. In haloarene substitution, NO₂ activates only the halogens ortho or para to it. A meta halogen stays put, and NO₂ itself is not the group that leaves.

Answer from the NTA final answer key. Solution by PrepWiser.

Study Halogen Derivatives — Haloalkanes & Haloarenes

Asked about 120 times in JEE Main since 2020. This question is from 2025.