Chemistry Aldehydes & Ketones MDCAT 2019
PMDC Verified Question 63 of 94
Which of the following compounds will give a secondary alcohol after reaction with \( NaBH_4 \)?
A
\( CH_3COCH_3 \)
B
\( CH_3CH_2CHO \)
C
\( CH_3CH_2COOH \)
D
\( CH_3COOCH_3 \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: \( CH_3COCH_3 \)
Concept:

Sodium borohydride (\( NaBH_4 \)) is a mild reducing agent that specifically reduces aldehydes and ketones to their corresponding alcohols.

Solution:

  • Aldehydes are reduced to primary alcohols.


  • Ketones are reduced to secondary alcohols.


  • Looking at the options, Option A (\( CH_3COCH_3 \)) is propanone, a ketone. Upon reduction by adding hydrogen across the double bond, it yields 2-propanol (\( CH_3CH(OH)CH_3 \)), which is a secondary alcohol.


Why other options are incorrect:

Option B is an aldehyde, which reduces to a primary alcohol (1-propanol). Options C and D are a carboxylic acid and an ester, respectively; \( NaBH_4 \) is too weak to efficiently reduce them (they require stronger agents like \( LiAlH_4 \)).

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