Solid State:
* Ionic Lattice: In the solid state, NaCl exists as a crystalline structure with a rigid ionic lattice. The sodium (Na+) and chloride (Cl-) ions are tightly held in fixed positions by strong electrostatic forces.
* No Free Charge Carriers: The ions are locked in place and cannot move freely. Therefore, there are no mobile charge carriers to carry an electric current.
* Insulator: As a result, solid NaCl acts as an insulator, preventing the flow of electricity.
Molten State:
* Liquid State: When NaCl melts, the ionic lattice breaks down, and the ions become free to move around randomly.
* Free Charge Carriers: These freely moving ions act as charge carriers. When a potential difference is applied, the positively charged sodium ions migrate towards the negative electrode, and the negatively charged chloride ions migrate towards the positive electrode.
* Conductive: The movement of these ions constitutes an electric current, making molten NaCl a good conductor of electricity.
In summary:
The difference in conductivity arises from the difference in the mobility of ions. In the solid state, ions are immobile, while in the molten state, they are free to move, allowing for the flow of electric current.
