Ion-Dipole Interactions (College Board AP Chemistry)

• This force which exists between an ion and a polar molecule, accounts for the dissolution of ionic compounds in polar solvents like water
• For example, in a solution of sodium chloride, NaCl, in water:
  • The oxygen atom has a partial negative (δ^-) charge
  • The hydrogen atoms have a partial positive charge (δ⁺)
  • Overall, there is a dipole moment within the water molecule
    • The Na⁺ ion is attracted to the negative end of the dipole
    • The Cl^- ion is attracted to the positive end of the dipole

Ion-Dipole Interactions

Ion-dipole interaction between sodium and chloride ions with water

• The magnitude of ion-dipole interactions increases as either the ionic charge or the magnitude of the dipole moment increases