Multiple Choice
Which of the following molecules cannot form hydrogen bonds with an identical molecule?
78
views
13. Liquids, Solids & Intermolecular Forces
Intermolecular Forces
Multiple Choice
Which of the following statements best explains why HBr has a higher boiling point than Br2?
A
Both HBr and Br2 have identical intermolecular forces, so their boiling points are the same.
B
Br2 forms hydrogen bonds, whereas HBr does not.
C
HBr exhibits dipole-dipole interactions in addition to London dispersion forces, while Br2 only has London dispersion forces.
D
HBr has a larger molecular mass than Br2, leading to stronger London dispersion forces.
Verified step by step guidance1
Step 1: Identify the types of intermolecular forces present in HBr and Br2. HBr is a polar molecule, so it exhibits dipole-dipole interactions and London dispersion forces. Br2 is a nonpolar molecule, so it only exhibits London dispersion forces.
Step 2: Understand that hydrogen bonding occurs only when hydrogen is directly bonded to highly electronegative atoms like N, O, or F. Since HBr has hydrogen bonded to bromine (not N, O, or F), it does not form hydrogen bonds.
Step 3: Recognize that dipole-dipole interactions are stronger than London dispersion forces alone, which means molecules with dipole-dipole forces generally have higher boiling points than nonpolar molecules of similar size.
Step 4: Compare molecular masses: Br2 has a higher molecular mass than HBr, so if boiling point differences were due only to London dispersion forces, Br2 would have the higher boiling point. However, the presence of dipole-dipole forces in HBr overrides this effect.
Step 5: Conclude that the higher boiling point of HBr compared to Br2 is best explained by the presence of dipole-dipole interactions in HBr in addition to London dispersion forces, while Br2 only has London dispersion forces.
Related Videos
Related Practice
