Question

Oils and fats are

• A. Higher alcohols
• B. Esters of higher acids
• C. Alkaloids
• D. Carbohydrates

Hint:

Oils and fats are triglycerides, formed as esters of glycerol and higher fatty acids, differing in their saturation (oils: unsaturated, liquid; fats: saturated, solid).

Answer 1

The Correct Option is B

Step 1: Define oils and fats. 
Oils and fats are lipids, organic compounds that are primarily used as energy storage molecules in living organisms. They are found in plants (e.g., vegetable oils) and animals (e.g., animal fats). Chemically, they are composed of glycerol (a triol) and fatty acids. 
Step 2: Analyze the chemical structure of oils and fats. 
Oils and fats are triglycerides, which are esters formed from one molecule of glycerol and three molecules of fatty acids (higher acids). Fatty acids are long-chain carboxylic acids (e.g., stearic acid, oleic acid), typically with 12–22 carbon atoms. The esterification reaction is: \[ \text{Glycerol} + 3 \text{Fatty Acids} \rightarrow \text{Triglyceride} + 3 \text{H}_2\text{O}. \] Oils are liquid at room temperature due to unsaturated fatty acids (e.g., olive oil).
Fats are solid at room temperature due to saturated fatty acids (e.g., butter).
Step 3: Evaluate the options. 
(1) Higher alcohols: Incorrect, as higher alcohols are compounds like cetyl alcohol (\( \text{C}_{16}\text{H}_{33}\text{OH} \)), not triglycerides. Oils and fats are esters, not alcohols. Incorrect.
(2) Esters of higher acids: Correct, as oils and fats are triglycerides, which are esters of glycerol and higher fatty acids (long-chain carboxylic acids). Correct.
(3) Alkaloids: Incorrect, as alkaloids are nitrogen-containing compounds (e.g., caffeine, nicotine), unrelated to oils and fats. Incorrect.
(4) Carbohydrates: Incorrect, as carbohydrates are sugars (e.g., glucose, starch), composed of carbon, hydrogen, and oxygen in the ratio 1:2:1, not esters like oils and fats. Incorrect.
Step 4: Select the correct answer. 
Oils and fats are esters of higher acids, matching option (2).