객관식
Which of the following solutions has the higher boiling point?
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14. Solutions
Boiling Point Elevation
객관식
Which of the following statements best explains why the boiling point of NBr3 is higher than that of NH3?
A
NBr3 forms hydrogen bonds, which increase its boiling point.
B
Both NBr3 and NH3 have similar boiling points because they are both nitrogen compounds.
C
NH3 has a higher boiling point because it is more polar than NBr3.
D
NBr3 has stronger London dispersion forces due to its larger molecular size compared to NH3.
검증된 단계별 안내1
Step 1: Understand the types of intermolecular forces present in NH3 and NBr3. NH3 (ammonia) is known to exhibit hydrogen bonding because it has N-H bonds, where hydrogen is directly bonded to a highly electronegative nitrogen atom.
Step 2: Recognize that NBr3 (nitrogen tribromide) does not have hydrogen atoms bonded to nitrogen, so it cannot form hydrogen bonds. Instead, its intermolecular forces are primarily London dispersion forces (induced dipole-induced dipole interactions).
Step 3: Compare the molecular sizes and molar masses of NH3 and NBr3. NBr3 has a much larger molar mass and a larger electron cloud due to the presence of bromine atoms, which increases the strength of London dispersion forces.
Step 4: Recall that boiling point is influenced by the strength of intermolecular forces. Stronger intermolecular forces require more energy (higher temperature) to overcome, leading to a higher boiling point.
Step 5: Conclude that although NH3 has hydrogen bonding, the much stronger London dispersion forces in the larger NBr3 molecule result in a higher boiling point for NBr3 compared to NH3.
