Question

Compound A from the following reaction sequence is 

• A. Benzoic acid
• B. Salicylic Acid
• C. Phenol
• D. Aniline

Answer 1

The Correct Option is D

The given reaction sequence involves the following steps: 

1. Step 1 (Bromination): In the presence of bromine (\( \text{Br}_2 \)) and carbon disulfide (\( \text{CS}_2 \)) at low temperature (\( 0-5^\circ \text{C} \)), aniline (\( \text{C}_6\text{H}_5\text{NH}_2 \)) undergoes electrophilic substitution at the para and ortho positions. The product \( \text{A} \) is: \[ \text{A} = \text{2,4,6-tribromoaniline}. \] 

2. Step 2 (Diazotization): The tribromoaniline reacts with sodium nitrite (\( \text{NaNO}_2 \)) and hydrochloric acid (\( \text{HCl} \)) to form a diazonium salt \( \text{B} \) (\( \text{C}_6\text{H}_2\text{Br}_3\text{N}_2^+\text{Cl}^- \)). 

3. Step 3 (Reduction): The diazonium salt \( \text{B} \) undergoes reduction with hypophosphorous acid (\( \text{H}_3\text{PO}_2 \)) and heat (\( \Delta \)) to produce the final compound \( \text{C} \), which is: \[ \text{C} = \text{2,4,6-tribromobenzene}. \] Since the starting compound is aniline and it undergoes transformation into 2,4,6-tribromobenzene, the answer is: \[ \boxed{\text{Aniline (Option 4)}}. \]