Melting and Boiling Points

[205154661_Dis2J]

Can we assume that melting and boiling points will always be higher for hydrogen bonds than any other intermolecular force?

[Connor Ho 1B]

Technically, yes. But the amount of forces a molecule has also plays a role, i.e. if a molecule experiences both h-bonding and dipole-dipole vs. h-bonding and LDF.

[Sartaj Bal 1J]

Usually, since H bonds are a stronger IMF, their melting and boiling points will be higher. For non polar molecules, these values increase as the molecules get larger because more LDF take place.

[Camille 4I]

What makes for a higher boiling point, ion-dipole interactions or hydrogen bonding?

[serenabirkhoff_1K]

What makes for a higher boiling point, ion-dipole interactions or hydrogen bonding?

Ion-dipole interactions are the strongest intermolecular force and therefore stronger than hydrogen bonding and therefore ion-dipole interactions have a higher boiling point.

[Ayushi2011]

I think the hierarchy is ionic>ionic-dipole>hydrogen>dipole-dipole>london forces (in terms of strength of interaction). Higher the strength, higher the temperature it needs to break the bond so higher melting point.

[ramiro_romero]

Ionic bonds will always create the highest boiling points, hydrogen bonds are just exceptionally strong dipole-dipole interactions. Follow the general rule ionic>hydrogen bonding>dipole dipole>London dispersion

[Ayushi2011]

ionic dipole is stronger than hydrogen bonding, so needs a higher melting point in order to break the bonds.

[Anna Heckler 2C]

Hydrogen bonds are, in essence, the strongest type of dipole-dipole interaction. Ionic bonds will always be stronger than dipole-dipole/H bond interactions.

[William Francis 2E]

Yes, I think that you can usually assume this. Hydrogen bonds only occur with Nitrogen, Oxygen, and Fluorine since these are the most electronegative atoms, so they can result in relatively strong dipoles.