Which statement about van der Waals forces is true?

• A. They only occur between polar molecules.
• B. They are responsible for the formation of ionic compounds.
• C. They are stronger than covalent bonds.
• D. They include both London dispersion forces and dipole-dipole interactions.

Answer: (D)

Verified step by step guidance

1. Understand that van der Waals forces are a type of intermolecular force, which means they occur between molecules rather than within molecules (like covalent or ionic bonds).
2. Recognize that van der Waals forces include two main types: London dispersion forces and dipole-dipole interactions. London dispersion forces arise from temporary fluctuations in electron distribution, and dipole-dipole interactions occur between polar molecules.
3. Note that van der Waals forces are not limited to polar molecules only, because London dispersion forces can occur between nonpolar molecules as well.
4. Recall that van der Waals forces are generally weaker than covalent bonds and are not responsible for the formation of ionic compounds, which involve electrostatic attraction between ions.
5. Conclude that the true statement about van der Waals forces is that they include both London dispersion forces and dipole-dipole interactions.