Ion-dipole interactions occur when the partial negative charge of a polar molecule (the dipole) interacts with an oppositely-charged ion. This type of interaction is important to understand when dealing with solutions and solvents, as the presence of polar molecules can affect the solubility of other compounds. The following pairs exhibit an ion-dipole interaction:

• NaCl and water: When NaCl dissolves in water, the Na⁺ ions become surrounded by the negative charge of the oxygen atoms in the water molecules, creating an ion-dipole interaction.
• KCl and methanol: When KCl dissolves in methanol, the K⁺ ions interact with the partial negative charge of the methanol molecules, creating an ion-dipole interaction.
• NaCl and ethanol: When NaCl dissolves in ethanol, the Na⁺ ions interact with the partial negative charge of the ethanol molecules, creating an ion-dipole interaction.
• MgCl₂ and acetic acid: When MgCl₂ dissolves in acetic acid, the Mg²⁺ ions interact with the partial negative charge of the acetic acid molecules, creating an ion-dipole interaction.

These ion-dipole interactions allow for the solubility of the compound in the solvent, and can have an effect on the molecule’s physical and chemical properties. This is why understanding these interactions can be important when studying different compounds and solutions.