Question

How would you explain the difference between van der Waals interaction and hydrophobic interaction?

Answer 1

Hint: When electrons are shared equally among two atoms connected via a chemical bond and the electronegativity difference between the atoms is negligible or the orientation of polar molecules cancel out each other then the molecule is known as nonpolar while if there exist an appreciable electronegativity difference between the bonded atoms then the molecule is termed as polar.

Complete answer:
The difference between given forces can be explained on the basis of polar and nonpolar molecule as follows:
Van der Waals interactions:
These are the chemical bonds formed between non-polar molecules. These types of interactions are either induced repulsive or attractive forces that are caused due to the change or fluctuation of polarization of neighbouring particles or molecules. These are categorized as a type of noncovalent bond and a weak force that may be attraction or repulsion acts between the two nonpolar molecules.
Hydrophobic interactions:
It is a specific type of interaction in which repulsive forces exist between the molecules of water and other substances. In the given term, hydro means water and phobic means fear. Hence, in simple words, we can say that the hydrophobic molecules or substances are water hating. Generally, these types of interactions are shown by nonpolar molecules as when these molecules are placed in water, the disordered hydrogen bond network in water is disrupted in the presence of a nonpolar molecule. So, the nonpolar molecules form a group together in order to maximize the amount of disordered water and hence, minimize the area of contact between the water and nonpolar molecules and as a result entropy of the system is decreased to its minimum value.

Note:
It is important to note that van der Waals forces generally occur in symmetrical molecules like hydrogen molecules and carbon dioxide molecules. Hydrophobic molecules are also termed as lyophilic substances as these substances have a tendency to attract lipid and fat components and thus, when added to water form clumps by combining to each other.