Which of the following best describes the effect of adding a nonvolatile solute to pure fluorine on its freezing point?

• A. Fluorine cannot experience freezing point depression.
• B. The freezing point of fluorine increases.
• C. The freezing point of fluorine remains unchanged.
• D. The freezing point of fluorine decreases.

Answer: (D)

Verified step by step guidance

1. Understand the concept of freezing point depression: When a nonvolatile solute is added to a pure solvent, the freezing point of the solvent decreases. This is a colligative property, meaning it depends on the number of solute particles, not their identity.
2. Recall that adding a nonvolatile solute lowers the chemical potential of the liquid phase, making it harder for the solvent molecules to organize into a solid structure, thus lowering the freezing point.
3. Recognize that this effect applies to all solvents, including fluorine, because the phenomenon depends on solute-solvent interactions and the disruption of the solvent's crystal lattice during freezing.
4. Eliminate incorrect options: The freezing point cannot increase or remain unchanged when a nonvolatile solute is added, and fluorine is not an exception to freezing point depression.
5. Conclude that the correct description is that the freezing point of fluorine decreases upon addition of a nonvolatile solute.