Question

Which of the following is incorrect with respect to the properties of lipids?

• A. They are readily soluble in organic solvents
• B. They have carbon, hydrogen and oxygen, though the content of oxygen is lower compared to that of carbon and hydrogen
• C. They function as food reserve in animals
• D. They yield lower energy per unit weight upon oxidation compared to carbohydrates

Answer 1

Answer: (D)

The oxidation states of the carbon atoms in carbohydrates are -1, 0, or +1, while the carbon atoms in lipids have oxidation states of -2 or -3. This means the carbon atoms in lipids have more electrons around them. With a more significant number of electrons around the carbon atoms in lipids transferred to oxygen (when the lipids are oxidized), more energy is released than when carbohydrates undergo the same process.

Properties of lipids:

• Lipids are hydrophobic in nature, so they are not soluble in water.
• The components of lipids are C: H:O, but the ratio is less for oxygen, i.e., 1:2:<1, which means they contain more carbon and are anhydrous.
• The lipids stored as an energy reserve can maintain the functions of the human body without food.