Question

Hydrophobic solutes are said to "force the adjacent water molecules to reorganize into icelike cages" (see the figure). The true cage of water molecules exists in three dimensions, forming a pentagonal dodecahedron (like a soccer ball) or clusters of them that enclose the hydrophobic solute. It seems paradoxical that water molecules do not interact with hydrophobic solutes, yet they seem to "know" about the presence of a hydrophobic solute and change their behavior to interact differently with one another. Which one of the following statements about the properties of icelike cages is correct?

1) An icelike cage can grow to form larger and larger crystals over time.
2) An icelike cage has a more ordered structure compared to liquid water.
3) Ice-like cages correspond to the maximum number of hydrogen bonds.
4) The presence of an icelike cage reduces the free energy of the solution.

Answer 1

The correct statement regarding icelike cages is that they have a more ordered structure compared to liquid water, due to the stable hydrogen bond network that forms in the cage-like arrangement.

Step-by-step explanation:

The question pertains to the phenomenon of water reorganizing around hydrophobic solutes to form structured, icelike cages. When considering which statement about the properties of icelike cages is correct, we can evaluate the options given based on the molecular behavior of water. The correct statement is that an icelike cage has a more ordered structure compared to liquid water. This happens because in an icelike cage, the water molecules are arranged in a rigid, lattice-like structure due to hydrogen bonding, which is not as prevalent in the fluid, dynamic state of liquid water where hydrogen bonds are continually formed and broken.