Question

Molten sodium chloride conducts electricity due to the presence of

• A. Free electrons
• B. Free molecules
• C. Atoms
• D. Free ions

Answer 1

The correct option is D

Free ions

A material must have charge particles, like electrons and ions, that are free to travel through it in order to conduct electricity.

The Sodium ($Na$) atoms and Chlorine ($Cl$) atoms separate when Sodium chloride ($NaCl$) dissolves in Water ($H_{2}O$) due to the effect of the water molecules. They're free to move about as positively and negatively charged ions in the water. The solution can conduct electricity because of the charge separation.

Explanation for correct option:

(D) Free ions

Ionic compounds like Sodium chloride ($NaCl$) have their ions set in place in the solid-state, so they can't move because they are tightly packed in the lattice structure. As a result, solid ionic compounds can't conduct electricity. Ions in ionic compounds are free to move in the molten state, hence molten Sodium chloride ($NaCl$) can conduct electricity.

Hence, the correct option is (D).