Question

What are X and Y in the following reaction sequence?
$C_6H_5N_2Cl \xrightarrow[H_2O]{283K} X \xrightarrow[OH^-]{C_6H_5N_2Cl} Y$

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

{Coupling Conditions:} Phenol: Alkaline medium ($pH 9-10$). Aniline: Acidic medium ($pH 4-5$).

Answer 1

The Correct Option is C

Step 1: Hydrolysis of Diazonium Salt:
Benzenediazonium chloride ($C_6H_5N_2Cl$) when warmed with water ($\textgreater283 K$ or simply stated as hydrolysis condition) yields Phenol ($C_6H_5OH$). So, $X = Phenol$.
Step 2: Coupling Reaction:
Reaction of Phenol (X) with Benzenediazonium chloride ($C_6H_5N_2Cl$) in alkaline medium ($OH^-$). This is the standard Diazo Coupling Reaction. Phenol couples primarily at the para-position (sterically favored and OH is activating). Product Y is p-Hydroxyazobenzene (an orange dye). Structure: $Ph-N=N-Ph-OH(p)$.
Step 3: Match Option:
Option (3) in the image shows the structure of p-Hydroxyazobenzene.