Stearic acid is classified as which type?

• A. Medium chain, 6-12 carbons
• B. Very long chain, 20+ carbons
• C. Short chain, 2-4 carbons
• D. Long chain, 18 carbons

Answer: (D)

Understanding how fatty acids are grouped by carbon chain length is what this item tests. Stearic acid has 18 carbon atoms, which places it in the long-chain fatty acid category. Short-chain fatty acids have about 2–4 carbons, medium-chain about 6–12, and very long-chain are 20 or more. Since 18 carbons fit the long-chain range, stearic acid is classified as a long-chain fatty acid.