Two molecules, A and B, have very different physical properties. A and B do not mix. Molecule A boils at 80°C and freezes at -30°C. Molecule B boils at 35°C and freezes at -100°C. Which molecule is likely to have the largest dipole?

Question

Quizplus · Accepted Answer

The size of the dipole moment of a molecule is proportional to the electronegativity difference between the atoms in the molecule and the distance between them. Since molecule A has a higher boiling point and melting point, it is likely to have a stronger intramolecular attractive force due to stronger van der Waals forces. This suggests that molecule A has a larger dipole moment compared to molecule B.

Two Molecules, a and B, Have Very Different Physical Properties