Chemistry Aldehydes & Ketones NUMS 2023
PMDC Verified Question 28 of 94
Catalytic reduction of aldehyde & ketones forms:
A
Alcohol
B
Carboxylic acid
C
Alkane
D
Aldehyde
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Alcohol
Concept:

Catalytic reduction involves the addition of hydrogen across a pi bond using a metal catalyst.

Formula:

$$ >C=O + H_2 \xrightarrow{Catalyst} >CH-OH $$

Solution:

  • When aldehydes and ketones are exposed to \( H_2 \) gas with a metal catalyst (Pd, Pt, Ni), the \( C=O \) pi bond is broken.


  • A hydrogen atom bonds to the carbon, and another bonds to the oxygen.


  • This transforms the carbonyl group into a hydroxyl group.


  • The resulting functional group is an Alcohol (primary from aldehydes, secondary from ketones).


Why other options are incorrect:

Carboxylic acids are oxidation products. Alkanes require aggressive deoxygenation (like Clemmensen), not mild catalytic hydrogenation. Aldehydes are the starting material, not the reduced product.

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