MHT CET202620 April 2026Morning ShiftChemistryAldehydes and KetonesActual
Which of the following reaction represents Rosenmund reduction ?
Options
- AR - CO - Cl [ Pd - BaSO ₄ ] H ₂ R - CHO + HCl
- BR - CN [ H ₃ O ^+ ] SnCl ₂, HCl R - CHO + NH ₄ Cl
- CR - CHO [ ] Zn - Hg conc.HCl R - CH ₃ + H ₂ O
- DR - CO - R [ ii) KOH, HO - CH ₂- CH ₂- OH , ] i) H ₂ N - NH ₂ R - CH ₂- R
Correct 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 con