Question

What are Y and Z respectively in the following reaction sequence?

• A.
• B.
• C.
• D.

Hint:

In electrophilic substitution, chlorine directs the incoming nitro group to the para-position due to its electron-withdrawing inductive effect.

Answer 1

The Correct Option is B

Step 1: Nitration of Chlorobenzene 
- Reaction: Chlorobenzene undergoes nitration with HNO\(_3\)/H\(_2\)SO\(_4\). 
- The major product is p-nitrochlorobenzene due to the electron-withdrawing effect of chlorine.
Step 2: Conversion to Phenol 
- Reaction: The chlorine in p-nitrochlorobenzene is replaced by OH under fused NaOH at high temperature (443K). 
- The resulting compound is p-nitrophenol.
Step 3: Confirming the Correct Option 
- The correct Y is p-nitrochlorobenzene.
- The correct Z is p-nitrophenol. 
Thus, the correct answer is the option with p-nitrophenol. \bigskip

Answer 2

We are given a reaction sequence starting from chlorobenzene.

Step 1: Chlorobenzene reacts with concentrated HNO₃ and concentrated H₂SO₄ (nitration conditions).
The major product of nitration of chlorobenzene is para-nitrochlorobenzene due to the electron-withdrawing yet ortho/para-directing nature of the chlorine atom.
So, compound X is para-nitrochlorobenzene.

Step 2: Compound X is then treated with:
(i) NaOH at 443 K (high temperature)
(ii) Followed by acidic hydrolysis (H⁺)
This is a nucleophilic aromatic substitution (SNAr) reaction, where the -Cl group is replaced by -OH.
The final product Z is para-nitrophenol.

Therefore:
Y = NaOH, 443 K followed by H⁺
Z = para-nitrophenol

Answer:
Y = NaOH / heat / H⁺ ; Z = para-nitrophenol