
Answer
Prediction of Final Product in a Multi-Step Organic Reaction
Step 1: Grignard Reaction
Reacting benzaldehyde with phenyl magnesium bromide (PhMgBr) followed by water results in a Grignard addition reaction.
- Phenyl group (Ph⁻) acts as a nucleophile.
- It attacks the electrophilic carbon of the aldehyde group.
- After protonation, a secondary alcohol is formed: diphenylmethanol (Ph2CHOH).
➤ Intermediate: Diphenylmethanol
Step 2: Oxidation with PCC (pyridinium chlorochromate)
The alcohol undergoes mild oxidation using PCC (in the presence of CrO3 and pyridine).
- PCC oxidizes secondary alcohols to ketones.
- The hydroxyl group of diphenylmethanol is converted into a carbonyl group (C=O).
➤ Intermediate: Benzophenone (Ph2CO)
Step 3: Oxidation with Na2Cr2O7 / H2SO4
This step typically performs strong oxidation, especially of benzylic positions or alcohols. However:
- Benzophenone is a ketone and cannot be oxidized further under these conditions.
- Therefore, the molecule remains unchanged in this step.
➤ Final Product: Benzophenone (Ph2CO)
Correct Option: A
Option A shows benzophenone, which is the correct final product.
✔️ Answer: Option A
