Question
Which of the following reaction represents Rosenmund reduction ?
MHT CET
Chemistry
Aldehydes and Ketones
2026
MHT CET 2026 (20 April Shift 1)
MHT CET Chemistry Question (2026) — Solution
Options
- A. R - CO - Cl [ Pd - BaSO _4 ] H _2 R - CHO + HCl
- B. R - CN [ H _3 O ^+ ] SnCl _2, HCl R - CHO + NH _4 Cl
- C. R - CHO [ ] Zn - Hg conc.HCl R - CH _3 + H _2 O
- D. R - CO - R [ ii) KOH, HO - CH _2- CH _2- OH ,\ ] i) H _2 N - NH _2 R - CH _2- R
Answer
A. R - CO - Cl [ Pd - BaSO _4 ] H _2 R - CHO + HCl
Step-by-step solution
Rosenmund reduction is the catalytic hydrogenation of an acid chloride to an aldehyde. The catalyst used is palladium on barium sulfate ( Pd - BaSO _4), which is partially poisoned to prevent further reduction of the aldehyde to an alcohol. The reaction is given by: R - CO - Cl [ Pd - BaSO _4] H _2 R - CHO + HCl The other reactions are: Stephen reaction: Reduction of nitriles to aldehydes using SnCl _2/ HCl followed by hydrolysis. Clemmensen reduction: Reduction of aldehydes or ketones to alkanes using Zn - Hg and conc. HCl . Wolff-Kishner reduction: Reduction of aldehydes or ketones to alkanes using hydrazine and a strong base like KOH in ethylene glycol. Answer: R - CO - Cl [ Pd - BaSO _4 ] H _2 R - CHO + HCl
Related: Chemistry — Aldehydes and Ketones · All PYQ Banks