Question

Explain why the $\mathrm{NaCl}$ is not a conductor of electricity in the solid state whereas it does conduct electricity in an aqueous solution as well as in a molten state?

Answer 1

$\mathrm{NaCl}$ does not conduct electricity in its solid state

• $\mathrm{NaCl}$ does not conduct electricity in the solid state whereas it does conduct electricity in an aqueous solution as well as in a molten state.
• $\mathrm{NaCl}$ is an ionic solid (solids formed by complete transference of electrons) and ionic solids conduct electricity only in a molten state but not in solids state.
• In a solid state, ions of the ionic compounds are not free to move.
• For the conduction of electricity, there must be the availability of free ions.
• Due to the unavailability of free ions in the solid state, ionic compounds are unable to conduct electricity in the solid state.

$\mathrm{NaCl}$ conduct electricity in an aqueous solution as well as in a molten state

• In ionic compounds, free ions are responsible for the conduction of electricity.
• In the case of molten state or solution form, there is the movement of ions which helps in the conduction of electricity.

Hence, $\mathrm{NaCl}$ conduct electricity in a molten state and solution form due to the presence of free ions in the solution while in solid state ions are not free to move.