MHT CET202618 April 2026Morning ShiftChemistryAldehydes and KetonesActual
Identify the reagent 'R' used in the following reaction C ₆ H ₅ COCl R C ₆ H ₅ CHO + HCl
Options
- ACO , HCl
- BH ₂, Pd - BaSO ₄
- CDIBAl - H
- DH ₂ O
Correct answer
B. H ₂, Pd - BaSO ₄
Step-by-step solution
The given reaction is the conversion of benzoyl chloride ( C ₆ H ₅ COCl ) to benzaldehyde ( C ₆ H ₅ CHO ). This transformation is known as the Rosenmund reduction. The reagent used for this reaction is hydrogen gas in the presence of a palladium catalyst supported on barium sulfate ( H ₂, Pd - BaSO ₄ ). The barium sulfate acts as a catalytic poison that partially deactivates the palladium, preventing the further reduction of the newly formed aldehyde into an alcohol. Thus, the reagent 'R' is H ₂, Pd - BaSO ₄ . Answ