Dipole Induced Dipole IMF

Summary

In this video, the concept of dipole-induced dipole interactions is explored, where a polar molecule induces a temporary dipole in a non-polar molecule. Using the example of water (polar) and iodine (non-polar), the video demonstrates how water can dissolve iodine through this interaction. The script explains the strength of these forces compared to other intermolecular forces like London dispersion forces, and highlights the polarizability of iodine as a key factor. The hierarchy of intermolecular forces is also presented, providing context for the significance of dipole-induced dipole interactions in chemical bonding.

Takeaways

• 😀 Dipole-induced dipole forces involve a polar molecule with a permanent dipole interacting with a non-polar molecule, temporarily inducing a dipole in the non-polar molecule.
• 😀 Non-polar molecules, like iodine, have a symmetrical electron distribution, meaning no permanent dipole. However, they can temporarily develop a dipole when exposed to a polar molecule like water.
• 😀 Water, being highly polar, has hydrogen bonding, dipole-dipole interactions, and London dispersion forces, making it capable of inducing a dipole in non-polar molecules.
• 😀 The water molecule’s partial negative charge on oxygen repels electrons in the iodine molecule, inducing a temporary dipole, which facilitates attraction between the two molecules.
• 😀 Larger molecules, such as iodine, are more easily polarizable due to their larger size and more extensive electron cloud, making them more susceptible to dipole-induced dipole interactions.
• 😀 The term 'polarizable' refers to the ease with which a molecule's electron distribution can be distorted, making it more likely to develop an induced dipole.
• 😀 Dipole-induced dipole interactions are stronger than London dispersion forces because of the presence of a permanent dipole in the polar molecule, which induces a temporary dipole in the non-polar molecule.
• 😀 In mixtures of substances, intermolecular forces follow a hierarchy with hydrogen bonding being the strongest, followed by ion-dipole, dipole-dipole, dipole-induced dipole, and London dispersion forces.
• 😀 Iodine dissolves in water due to dipole-induced dipole interactions, despite iodine being non-polar, because the water molecule induces a dipole in iodine that leads to intermolecular attraction.
• 😀 Dipole-induced dipole interactions are more significant than London dispersion forces because they involve a permanent dipole inducing a temporary dipole, whereas London dispersion forces involve temporary dipoles without the influence of a permanent dipole.

Q & A

What is the main concept behind dipole-induced dipole interactions?

Dipole-induced dipole interactions occur when a polar molecule with a permanent dipole induces a temporary dipole in a nonpolar molecule. The temporary dipole forms due to the repulsion of electrons in the nonpolar molecule caused by the partial charges in the polar molecule.

Why do iodine molecules form dipole-induced dipole interactions with water?

Iodine molecules are nonpolar but large in size, making them easily polarizable. When water, a highly polar molecule, is brought close to iodine, its partial negative charge (from oxygen's lone pairs) repels electrons in iodine, inducing a temporary dipole that attracts the permanent dipole of water.

What makes iodine easily polarizable?

Iodine is easily polarizable because it is a large molecule with many electrons. Its size and electron cloud distribution allow for a temporary dipole to be induced when interacting with a polar molecule like water.

How does water induce a temporary dipole in iodine?

Water, being highly polar, has partial negative and positive charges. As water comes close to iodine, its partial negative charge (from oxygen's lone pairs) repels electrons in the iodine molecule, causing the electrons to shift, which induces a temporary dipole in iodine.

What is the significance of the term 'polarizable' in the context of dipole-induced dipole interactions?

'Polarizable' refers to the ability of a molecule, especially a nonpolar one like iodine, to form a temporary dipole when influenced by the electric field of a nearby polar molecule. The larger and more electron-rich the molecule, the more easily it can be polarized.

Why is iodine considered a quintessential example of a nonpolar molecule?

Iodine is considered a quintessential example of a nonpolar molecule because the two iodine atoms have identical electronegativities, leading them to share electrons equally. This results in a molecule with no permanent dipole moment.

Why do some nonpolar molecules, like iodine, dissolve in polar solvents like water?

Nonpolar molecules like iodine can dissolve in polar solvents like water due to dipole-induced dipole interactions. Water induces a temporary dipole in iodine, allowing the two to interact and form a solution, despite their apparent polarity difference.

What is the general hierarchy of intermolecular forces from strongest to weakest?

The general hierarchy of intermolecular forces, from strongest to weakest, is: hydrogen bonding > ion-dipole > dipole-dipole > dipole-induced dipole > London dispersion forces.

Why is dipole-induced dipole interaction stronger than London dispersion forces?

Dipole-induced dipole interactions are stronger than London dispersion forces because they involve a permanent dipole inducing a temporary dipole in a nonpolar molecule, which leads to a more significant and consistent attraction than the fleeting and less intense dipoles formed in London dispersion forces.

How does the large size of iodine contribute to its ability to interact with water?

Iodine's large size gives it a greater surface area and more electrons, making it easier for water to induce a temporary dipole in iodine. This increased polarizability helps iodine interact with the highly polar water molecules, leading to dissolution despite iodine's nonpolar nature.