Chemistry Carboxylic Acids DUHS 2023
PMDC Verified Question 32 of 94
What is the IUPAC name of stearic acid?
A
Hexanoic acid
B
Octadecanoic acid
C
Octanoic acid
D
Hexadecanoic acid
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Octadecanoic acid
Concept:

Stearic acid is one of the most common long-chain saturated fatty acids found in animal and vegetable fats.

Formula:

$$ \text{CH}_3(\text{CH}_2)_{16}\text{COOH} $$

Solution:

  • Stearic acid has a continuous straight carbon chain consisting of exactly 18 carbon atoms.


  • In IUPAC nomenclature, the 18-carbon alkane is octadecane.


  • Adding the standard acid suffix gives octadecanoic acid.


Why other options are incorrect:

Hexanoic acid has 6 carbons. Octanoic acid has 8 carbons. Hexadecanoic acid has 16 carbons (known commonly as palmitic acid).

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