Q. In the reaction 2-bromo-4-nitrobenzenediazonium chloride —(A)→ m-bromonitrobenzene A is
A) HgSO₄/H₂SO₄
B) Cu₂Cl₂
C) H₃PO₂ and H₂O
D) H⁺/H₂O
Explanation
[Solution from source] Removing the diazonium group at C-1 leaves Br at C-2 and NO₂ at C-4, which are meta to each other, so the reagent must replace –N₂⁺ by H. Hypophosphorous acid (H₃PO₂) with water does this. Cu₂Cl₂ would introduce Cl and H⁺/H₂O would give a phenol. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.