What is the primary reason ionic compounds conduct electricity in aqueous or molten states?

Ionic compounds conduct electricity in aqueous or molten states primarily due to the movement of ions. In these states, the ionic bonds that hold the compound together are broken, allowing the ions to become free to move. When a voltage is applied to an ionic solution or molten ionic compound, these free ions can move towards the respective electrodes – cations migrate towards the negative electrode (cathode), while anions move towards the positive electrode (anode). This movement of charged particles enables the conduction of electricity, as it creates a flow of electric charge.

In contrast, in solid-state ionic compounds, the ions are fixed in place within a rigid lattice structure and cannot move freely, which prevents them from conducting electricity. The other responses focus on concepts that do not pertain to the conductivity of ionic compounds under these conditions, such as the movement of electrons or pressure applied to the substance, neither of which are responsible for the conduction mechanisms in ionic compounds.