Fats and oils are esters of fatty organic acids combined with a trihydric alkanol commonly referred to as

Step 1: Analyze the question The question asks for the name of the trihydric alkanol (an alcohol with three –OH groups) that combines with fatty acids to form fats and oils.

Step 2: Explain the concept

• Fats and oils are triglycerides, which are triesters.
• They form when one molecule of an alcohol with three –OH groups reacts with three molecules of fatty acids (esterification).
• "Trihydric" means three hydroxyl groups.

Step 3: Check each option

• A. Ethanol (C₂H₅OH): one –OH group, so it is monohydric. ✗
• B. Methanol (CH₃OH): one –OH group, so it is monohydric. ✗
• C. Glycol (ethane-1,2-diol, HOCH₂CH₂OH): two –OH groups, so it is dihydric. ✗
• D. Glycerol (propane-1,2,3-triol, HOCH₂CH(OH)CH₂OH): three –OH groups, so it is trihydric. ✓

Step 4: Show the reaction

Glycerol + 3 Fatty acids → Triglyceride (fat or oil) + 3 H₂O

The three –OH groups on glycerol each form an ester linkage with one fatty acid (RCOOH).

Answer: D. Glycerol

Exam tip: Remember the prefixes by the number of –OH groups: mono = 1 (ethanol), di = 2 (glycol), tri = 3 (glycerol). Also, when fats are hydrolysed with NaOH (saponification), you get soap + glycerol. JAMB likes to test this link.