Which of the following best describes dispersion forces in mixtures?

• A. Dispersion forces only occur between polar molecules in mixtures.
• B. Dispersion forces are a type of ionic bond present in mixtures.
• C. Dispersion forces are stronger than hydrogen bonds in all mixtures.
• D. Dispersion forces arise from temporary fluctuations in electron density, leading to instantaneous dipoles that can occur between any molecules, including those in mixtures.

Answer: (D)

Verified step by step guidance

1. Understand that dispersion forces, also known as London dispersion forces, are a type of intermolecular force that arise due to temporary fluctuations in the electron distribution within molecules or atoms.
2. Recognize that these temporary fluctuations create instantaneous dipoles, which induce dipoles in neighboring molecules, resulting in an attractive force between them.
3. Note that dispersion forces can occur between any molecules, whether they are polar or nonpolar, because all molecules have electrons that can fluctuate momentarily.
4. Distinguish dispersion forces from other intermolecular forces such as hydrogen bonding (which requires specific atoms like H bonded to N, O, or F) and ionic bonds (which are strong electrostatic attractions between ions).
5. Conclude that dispersion forces are generally weaker than hydrogen bonds but are universal and present in all mixtures, making them a fundamental type of intermolecular interaction.