Hydrogen Bonding and Boiling Point
"On the Effect of Hydrogen Bonding on the Boiling Point"
The boiling point of a human substance is related to many factors, and the effect of hydrogen bonding is particularly significant. Hydrogen bonding is a weak interaction between hydrogen atoms and atoms with large electronegativity and small radius (such as fluorine, oxygen, nitrogen, etc.).
Looking at all substances, those containing hydrogen bonds often have boiling points that are different from common sense. Taking water as an example, according to common sense, the boiling point of hydrides in the same main group increases with the increase of relative molecular mass, but the boiling point of water is only higher. The hydrogen bond can be formed between water molecules. The force of this hydrogen bond makes the water molecules attract each other and agglomerate more tightly. To make it boil, more energy is required to break the hydrogen bond, so the boiling point of water is much higher than that of hydrogen sulfide equivalent group hydrides.
And look at alcohols. Hydroxyl groups in ethanol molecules can form hydrogen bonds, which are much higher than alkanes with similar molecular weights. This is because alkanes only have van der Waals force, which is weak, while ethanol has hydrogen bonds in addition to van der Waals force, which increases the intermolecular force, and the boiling point rises.
Looking at the hydrogen bonds between nitrogen-containing compounds and ammonia molecules, the boiling point of ammonia is higher than that of other hydrides of the same family. When heating makes ammonia boil, the force of hydrogen bonds must be overcome before ammonia can be converted from liquid to gaseous.
In summary, hydrogen bonds have a deep impact on the boiling point of a substance. Where hydrogen bonds can be formed between molecules of a substance, the intermolecular force increases, and the boiling point also rises. This is a key factor that cannot be ignored when exploring the physical properties of a substance.
The boiling point of a human substance is related to many factors, and the effect of hydrogen bonding is particularly significant. Hydrogen bonding is a weak interaction between hydrogen atoms and atoms with large electronegativity and small radius (such as fluorine, oxygen, nitrogen, etc.).
Looking at all substances, those containing hydrogen bonds often have boiling points that are different from common sense. Taking water as an example, according to common sense, the boiling point of hydrides in the same main group increases with the increase of relative molecular mass, but the boiling point of water is only higher. The hydrogen bond can be formed between water molecules. The force of this hydrogen bond makes the water molecules attract each other and agglomerate more tightly. To make it boil, more energy is required to break the hydrogen bond, so the boiling point of water is much higher than that of hydrogen sulfide equivalent group hydrides.
And look at alcohols. Hydroxyl groups in ethanol molecules can form hydrogen bonds, which are much higher than alkanes with similar molecular weights. This is because alkanes only have van der Waals force, which is weak, while ethanol has hydrogen bonds in addition to van der Waals force, which increases the intermolecular force, and the boiling point rises.
Looking at the hydrogen bonds between nitrogen-containing compounds and ammonia molecules, the boiling point of ammonia is higher than that of other hydrides of the same family. When heating makes ammonia boil, the force of hydrogen bonds must be overcome before ammonia can be converted from liquid to gaseous.
In summary, hydrogen bonds have a deep impact on the boiling point of a substance. Where hydrogen bonds can be formed between molecules of a substance, the intermolecular force increases, and the boiling point also rises. This is a key factor that cannot be ignored when exploring the physical properties of a substance.

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