[Campbell Biology P.98] The text describes cotton as a hydrophilic substance that does not ... | Practice Question

The text describes cotton as a hydrophilic substance that does not dissolve in water. Which of the following best explains why cotton, despite being hydrophilic, does not dissolve?

  • A: Cotton molecules are nonionic and nonpolar, thus repelling water.
  • B: Cotton consists of giant molecules of cellulose, and while it has regions that can form hydrogen bonds with water, its large size prevents complete dissolution.
  • C: Cotton's fibers are too tightly packed for water molecules to penetrate and interact with them.
  • D: Cotton forms strong covalent bonds with water, making it insoluble.

Explanation

The text explains that cotton is hydrophilic due to numerous regions of partial positive and negative charges that can form hydrogen bonds with water. However, it also states that cotton consists of 'giant molecules of cellulose', implying that its large molecular size is the reason it does not dissolve, even though water adheres to its fibers.