Question

What are X, Y and Z in the given reaction sequence?

 

• A.
• B.
• C.
• D.

Hint:

High temperatures and pressures are often necessary to facilitate reactions involving aromatic ring substitutions, particularly when strong resonance stabilization must be overcome.

Answer 1

The Correct Option is A

Step 1: Determine the reactants and conditions for each transformation. X is initially chlorobenzene.
Y involves the conversion of chlorobenzene using strong base and heat, likely aiming for a substitution reaction that introduces a hydroxyl group, leading to phenol.
Z would then be the final product, phenol, under the given reaction conditions.
Step 2: Confirm the specific conditions and product. The conditions described (NaOH at 623 K and 300 atm) are indicative of a high-pressure, high-temperature environment suitable for converting chlorobenzene to phenol, a process that involves breaking the aromatic ring's stability to introduce the hydroxyl group.

Answer 2

To solve the problem, we need to determine the compounds X, Y, and Z in the given reaction sequence involving a chlorinated compound.

1. Understanding the Reaction Sequence:
The given reaction sequence is: \[ X \xrightarrow{CHCl_3/\text{NaOH}} Y \xrightarrow{H^+} Z \] This reaction involves chlorination and subsequent hydrolysis, where the compound undergoes a transformation under basic conditions and acidic conditions.
Step 1: The first reaction involves chlorination (using CHCl3 and NaOH). This suggests that compound X is likely a phenol, and the reaction is a Reimer-Tiemann reaction where phenol is chlorinated to form ortho- or para-hydroxy benzaldehyde.
Step 2: The second reaction involves hydrolysis under acidic conditions. The major product formed under these conditions suggests that compound Y is likely a benzyl alcohol (as it undergoes reduction to an alcohol under the action of H+). Thus, the sequence leads us to identify X as phenol, Y as an intermediate product, and Z as benzaldehyde.

2. Identifying the Correct Answer:
From the given options, Option 1 describes the correct sequence of reactions, with X being phenol, Y being an intermediate, and Z being benzaldehyde under the given reaction conditions.

Final Answer:
The correct answer is Option A.