Select all the intermolecular forces associated with NaCl salt.
A. Ion-dipole
B. Dipole-dipole
C. H-bonding
D. London Dispersion
The correct answer and explanation is :
The correct intermolecular force associated with NaCl (sodium chloride) in its dissolved state (in solution) is A. Ion-dipole.
Explanation:
Sodium chloride (NaCl) is an ionic compound, meaning it is composed of ions: Na⁺ (sodium ions) and Cl⁻ (chloride ions). When NaCl dissolves in a polar solvent like water, it dissociates into these ions. The intermolecular forces that occur between the dissolved NaCl and the solvent molecules primarily involve ion-dipole interactions.
- Ion-Dipole Interactions: This is the primary type of intermolecular force in NaCl dissolved in water. Water molecules are polar, meaning they have a positive and a negative end (due to the oxygen atom being partially negative and the hydrogen atoms being partially positive). When NaCl dissolves in water, the positive Na⁺ ions are attracted to the negative oxygen atoms of water molecules, and the negative Cl⁻ ions are attracted to the positive hydrogen atoms of water molecules. These attractive forces between the ions and the dipoles of the water molecules are known as ion-dipole interactions.
- Dipole-Dipole Interactions: This type of force occurs between polar molecules. However, NaCl is not a polar molecule but rather an ionic compound. Therefore, dipole-dipole interactions do not apply to NaCl itself, though they do apply to the water molecules surrounding NaCl in solution.
- Hydrogen Bonding (H-bonding): Hydrogen bonding occurs between a hydrogen atom bonded to a highly electronegative atom (like oxygen, nitrogen, or fluorine) and another electronegative atom. While water molecules engage in hydrogen bonding among themselves, NaCl itself does not participate in hydrogen bonding because it is an ionic compound.
- London Dispersion Forces: These are weak, temporary interactions that occur in all molecules due to instantaneous dipoles. While London dispersion forces are present in all molecules, they are not the primary intermolecular force between NaCl and water. These forces are far weaker than ion-dipole interactions and thus play a minor role in NaCl dissolution.
In conclusion, the primary intermolecular force present when NaCl dissolves in water is ion-dipole interaction (A).