Dipole-Dipole vs Dipole-Induced Dipole

[Lauren Mozier 1J]

Hi what is the difference between dipole-dipole and dipole-induced dipole? Why is dipole-dipole stronger than dipole-induced dipole? Can you also provide and example please thank you!

[406433397]

Hi! So dipole-dipole forces is the attraction between two polar molecules- the slightly negative section of one molecule will attract the slightly positive section of the other. Dipole-induced dipole is between one polar molecule and one non-polar molecule. This happens because the polar molecule will distort the electron configuration for a little bit of the non-polar molecule to create the slightly negative or positive charge. This means that the dipole-induced dipole is going to be weaker because it is not permanently charged if that makes sense so the attraction between the molecules will be much weaker. It is also usually only for a short period of time. Hope this helps!

[Tamer Siam 2F]

Dipole-dipole is the interaction between two molecules that have "poles" in their molecular structure (partial positive and partial negative), and the opposite partial charges are attracted to each other. Dipole-induced dipole is the interaction between one of these molecules that has a partial positive and partial negative, and another molecule that typically doesn't have a dipole, but is "induced" by the dipole molecule, creating a temporary partial positive/negative to be attracted to. A temporary pole has a weaker attraction compared to a molecule that possesses a dipole on its own, hence the weaker interaction.

Ex. H-Cl (dipole) and N2. H-Cl has a high dipole moment due to the electronegativity difference between hydrogen and chlorine.
When H-Cl gets close to N2, Cl can push electrons away on N2, forming a partial positive on the side closest and a partial negative on the side farther away, creating an induced dipole.