Chemistry Carboxylic Acids NUMS 2019
PMDC Verified Question 62 of 94
Which of the following is not a fatty acid?
A
Phenyl acetic acid
B
Stearic acid
C
Palmitic acid
D
Oleic acid
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Phenyl acetic acid
Concept:

By definition, true fatty acids are long-chain aliphatic (straight-chain, non-aromatic) carboxylic acids found in fats and oils.

Solution:

  • Stearic acid (C18), Palmitic acid (C16), and Oleic acid (C18, unsaturated) are classic aliphatic fatty acids derived from biological lipids.


  • Phenyl acetic acid contains an aromatic benzene ring (\( \text{C}_6\text{H}_5\text{CH}_2\text{COOH} \)). Aromatic acids are structurally distinct and are excluded from the biochemical definition of fatty acids.


Why other options are incorrect:

Options B, C, and D accurately represent biological fatty acids.

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