What is the conductivity of salts?
Salts conduct electricity only when molten or in solution; otherwise, they do not conduct electricity.
Salts are ionic compounds. Ionic compounds cannot conduct electricity when solid because, although they are entirely composed of charged particles called ions, these ions are not free to move: a factor vital to conduction of electricity.
This static inertia is not maintained when the compound is melted. This is because the ions have sufficient energy to overcome the electrostatic attraction that draws them together and move away from one another. As they are able to move, the ions are free to conduct electrical current.
The same thing occurs when you dissolve a salt in an appropriate solvent, such as water. The ions split apart, or dissociate, due to the polarity of the water. As such, the ions are free to move through the liquid to conduct a current.