To determine which of the given compounds has the highest boiling point, we need to analyze the types and strengths of intermolecular forces present in each compound. The higher the strength of these intermolecular forces, the higher the boiling point of the compound.
1. CH3OCH3 (dimethyl ether):
- Intermolecular Forces: Dipole-dipole interactions and London dispersion forces (Van der Waals forces).
- Strength of Forces: Moderate due to dipole-dipole interactions.
2. CH3OH (methanol):
- Intermolecular Forces: Hydrogen bonding (due to -OH group), dipole-dipole interactions, and London dispersion forces.
- Strength of Forces: Strong due to hydrogen bonding.
3. H₂O (water):
- Intermolecular Forces: Hydrogen bonding (each water molecule can form up to four hydrogen bonds), dipole-dipole interactions, and London dispersion forces.
- Strength of Forces: Very strong due to multiple hydrogen bond formations.
4. HF (hydrogen fluoride):
- Intermolecular Forces: Hydrogen bonding (hydrogen atom bonded to highly electronegative fluorine), dipole-dipole interactions, and London dispersion forces.
- Strength of Forces: Strong due to hydrogen bonding.
Now, compare the strengths and effects of these intermolecular forces on boiling points:
- CH3OCH3 has the weakest intermolecular forces due to only having dipole-dipole interactions and London dispersion forces.
- CH3OH, HF, and H₂O all exhibit hydrogen bonding, which is the strongest type of intermolecular force present among the given options.
- Among CH3OH, HF, and H₂O, water (H₂O) stands out because it can form more hydrogen bonds per molecule compared to methanol (CH3OH) and hydrogen fluoride (HF).
Therefore, the compound with the highest boiling point is expected to be H₂O (water) due to its ability to form multiple and strong hydrogen bonds. Thus, the correct answer is C) H₂O.
