What is a property of ionic compounds when they are melted or dissolved in water?

Ionic compounds, when melted or dissolved in water, dissociate into their constituent ions. This process allows them to conduct electricity. The presence of free-moving charged particles, such as cations and anions, is essential for electrical conductivity. In the solid state, ionic compounds form a rigid lattice structure that does not allow ions to move freely; however, once melted or dissolved, the ions can move independently, allowing the solution or molten compound to effectively conduct an electric current.

For this reason, the ability to conduct electricity is a defining property of ionic compounds in the molten state or in a solution, making this answer correct. Other options suggest that ionic compounds either do not conduct electricity, fail to dissolve, or transform into gases, all of which do not accurately describe the behavior of ionic compounds when melted or dissolved in water.