Choose the correct sequence of reagents to carry out the following conversion:

(A) Conc. $HNO_3$/Conc. $H_2SO_4$
(B) $Sn/HCl$
(C) $Br_2/FeBr_3$
(D) $NaNO_2/HCl$; followed by boiling with water

Choose the correct answer from the options given below:

(A), (C), (B), (D)

The correct answer is Option (1) → (A), (C), (B), (D) 

To convert Benzene to m-bromophenol, the sequence of reagents must ensure that the bromine atom is placed in the meta position relative to the eventual hydroxyl ($-OH$) group. Because the $-OH$ group is ortho/para-directing, it cannot be added first.

The most common synthetic route involves using a nitro group as a meta-directing intermediate:

Reagent Sequence

Detailed Chemical Mechanism

1. Nitration: The nitronium ion ($NO_2^+$) replaces a hydrogen on benzene. The resulting nitro group is a strongly deactivating meta-director.

2. Bromination: In the presence of the nitro group, the incoming bromine electrophile is directed to the meta position.

3. Functional Group Transformation:

• The nitro group is reduced to an amino group ($-NH_2$).
• The amino group is converted into a diazonium salt ($-N_2^+Cl^-$) using nitrous acid.
• Heating the diazonium salt with water replaces the diazonium group with a hydroxyl group ($-OH$), yielding the final product.