Which factor primarily determines the strength of dipole-dipole interactions between molecules?

• A. The presence of hydrogen atoms in the molecules
• B. The molecular mass of the compounds
• C. The number of valence electrons in the molecules
• D. The magnitude of the molecular dipole moments

Answer: (D)

Verified step by step guidance

1. Understand that dipole-dipole interactions occur between polar molecules, where there is a separation of positive and negative charges within the molecule.
2. Recognize that the strength of dipole-dipole interactions depends on how strongly the positive end of one molecule attracts the negative end of another molecule.
3. Identify that this attraction strength is directly related to the magnitude of the molecular dipole moment, which quantifies the polarity of the molecule.
4. Note that factors like the presence of hydrogen atoms, molecular mass, or number of valence electrons do not directly determine dipole-dipole interaction strength unless they affect the dipole moment.
5. Conclude that the primary factor determining the strength of dipole-dipole interactions is the magnitude of the molecular dipole moments, as it reflects the extent of charge separation and polarity.