Question

The final product R is

• A.
• B.
• C.
• D.

Answer 1

The Correct Option is C

In the first step, bromine reacts with nitrobenzene in the presence of FeBr₃, forming a bromonitrobenzene derivative (product \( P \)).
In the second step, sodium nitrite (\( \text{NaNO}_2 \)) at 273 K reacts with the product to form a diazonium salt (\( Q \)).
In the third step, the diazonium salt reacts with dilute HCl to produce a phenol derivative.
Finally, when the reaction mixture is warmed with water, the diazonium group is replaced by a hydroxyl group, forming \( \text{OH} \, \text{Br} \) as the final product, which corresponds to option (C).

Thus, the final product \( R \) is \( \text{OH} \, \text{Br} \).

Answer 2

The reaction sequence begins with a nitrobenzene compound undergoing halogenation in the presence of \( \text{FeBr}_3 \), which gives a bromonitrobenzene (P). Next, the bromonitrobenzene is treated with tin and concentrated hydrochloric acid, leading to a reduction that converts the nitro group into an amine group (Q). Then, when the reaction is treated with sodium nitrite (\( \text{NaNO}_2 \)) at 273 K in dilute HCl, the amine group undergoes diazotization, producing a diazonium salt. Finally, heating the diazonium salt in the presence of warm water leads to the substitution of the diazonium group by a hydroxyl group, resulting in the final product, phenol.

Thus, the final product (R) is a hydroxylated compound with a bromine on the ring, which corresponds to option (C).