Chemistry - CHEMICAL BONDING Question with Solution | TestHub
Assertion: The supplied normal boiling-point data, CH₃Cl=249 K, CH₃Br=277 K, CH₃I=315 K, show an increase down the series even though permanent molecular dipole moment decreases.
Reason: Increasing electron-cloud polarizability strengthens dispersion enough to outweigh the decrease in permanent-dipole contribution for this series.
Choose the best evaluation, then use it to assess the claim "larger dipole moment always means higher boiling point".
Options:
Answer:
Solution:
The increasing listed boiling points establish the assertion independently of dipole size. The larger and more polarizable halogen cloud strengthens London interactions; this is the relevant competing effect. Thus the reason explains this trend and provides a counterexample to the universal dipole-only rule. Boiling reflects the combined intermolecular interactions, not a ranking by a single molecular property.
