Chapter 23, Problem 5TE

To determine

The reason due to which lipids are insoluble in water.

Answer to Problem 5TE

Lipid molecules are non-polar whereas water is polar molecule. This is the only reason due to which lipids are insoluble in water.

Explanation of Solution

Lipids or fats are compound of biological origin that dissolves in nonpolar solvent such as chloroform and ethanol. Water is a type of polar solvent. Lipids being hydrophobic are insoluble in water and as the result of this water molecules could not attach with lipid molecules. This is the only reason due to which oil floats over the surface of water when mixed into it.

The lipid layer is immiscible with the layer of water as the result of this a boundary is clearly visible which is evident for the two separated layers are found in the mixture of lipid and water.

Conclusion:

Lipid molecules are non-polar in nature and therefore get easily soluble in organic solvents like chloroform. However, they are water hating due to which they are insoluble in polar solvent like water.