Why does molten (liquid) sodium chloride conduct electricity?

• A. Because the liquid contains neutral molecules that facilitate electron transfer.
• B. Because the Na^+ and Cl^- ions are free to move and carry electric current.
• C. Because sodium atoms release electrons that flow through the liquid.
• D. Because the chloride ions form covalent bonds with sodium, allowing electron flow.

Answer: (B)

Verified step by step guidance

1. Understand that electrical conductivity in substances depends on the presence of charged particles that can move freely to carry electric current.
2. Recognize that solid sodium chloride (NaCl) is an ionic compound where Na^+ and Cl^- ions are held rigidly in a crystal lattice, preventing ion movement and thus conductivity in solid form.
3. When sodium chloride is molten (liquid), the crystal lattice breaks down, allowing the Na^+ and Cl^- ions to move freely throughout the liquid.
4. These free-moving ions act as charge carriers, with Na^+ ions moving toward the negative electrode and Cl^- ions moving toward the positive electrode, enabling the flow of electric current.
5. Therefore, molten sodium chloride conducts electricity because it contains mobile ions (Na^+ and Cl^-) that facilitate charge transport, not because of neutral molecules or electron flow from atoms.