In the following reaction:

Step 1: Identify the starting material

From the image: Aromatic compound with:

• $\ce{-CH3}$ group (methyl)
• $\ce{-CCl3}$ group (trichloromethyl)

Likely: p-Chlorotoluene derivative or similar

Step 2: Reaction with O₂ (oxidation)

The $\ce{-CCl3}$ group can be oxidized:

$\ce{Ar-CCl3 + O2 -> Ar-C(=O)OOH}$

Forms peroxy acid intermediate

Step 3: Hydrolysis with H₂/H₂O

Peroxy acid undergoes hydrolysis:

$\ce{Ar-C(=O)OOH ->[H2O] Ar-COOH}$

Forms carboxylic acid

But wait, the question shows products A and B, suggesting two products.

Alternative interpretation:

If the starting material has both $\ce{-CH3}$ and $\ce{-CCl3}$:

1. $\ce{-CCl3}$ oxidizes to $\ce{-COOH}$
2. $\ce{-CH3}$ might also oxidize

Or the $\ce{-CCl3}$ hydrolyzes to $\ce{-COOH}$, then decarboxylates to $\ce{-OH}$.

Given answer (a) shows p-cresol ($\ce{p-CH3-C6H4-OH}$), this suggests:

Final products:

• A: p-Cresol (phenol with methyl group)
• B: Likely $\ce{CHCl3}$ or $\ce{CO2}$

Answer: (a) p-Cresol

Key Reactions:

Oxidation of side chains:

• Benzylic positions are easily oxidized
• $\ce{Ar-CH3 ->[KMnO4] Ar-COOH}$
• $\ce{Ar-CCl3 ->[O2] Ar-COOH}$

Hydrolysis of trichloromethyl: $\ce{Ar-CCl3 + H2O -> Ar-COOH + 3 HCl}$

Decarboxylation: $\ce{Ar-COOH ->[heat] Ar-H + CO2}$

Or in presence of base: $\ce{Ar-COOH ->[OH-] Ar-O- + CO2}$