Question

11-10 Water molecules readily form hydrogen bonds with other polar molecules, and when they

encounter nonpolar molecules they must form hydrogen-bonding networks with
neighboring water molecules. Which of the following molecules will cause a "cage" of
water to form?
(a) 2-methylpropane
(b) acetone
(c) methanol
(d) urea

Answer 1

2-methylpropane is the molecule that will cause a "cage" of water to form because it is nonpolar; water molecules cannot form hydrogen bonds with nonpolar substances and instead form a structured network around such molecules.

Step-by-step explanation:

When water encounters nonpolar molecules, the water molecules form a structured network or "cage" around the nonpolar molecules due to their inability to form hydrogen bonds with these hydrophobic substances. Given the molecules listed:

• 2-methylpropane is a nonpolar molecule due to its symmetric structure, causing water to form a "cage" around it.
• Acetone, methanol, and urea are all polar molecules. They contain polar groups that can interact with the polar H of water, and thus, they will not trigger the formation of a "cage" like structure by water molecules.

The molecule that will cause a "cage" of water to form around it is 2-methylpropane (a).