Explain why ionic compounds must be molten or dissolved in water for electrolysis to occur.

Ionic compounds must be molten or dissolved in water to allow their ions to move freely. In solid state, the ions are held in a rigid lattice structure and cannot conduct electricity. When molten or dissolved, the ionic bonds break, enabling the ions to move towards the electrodes during electrolysis.

This answer is strong because it clearly states the necessity of free-moving ions for conduction and links it to the physical state of the ionic compound. The question tests the understanding of the conditions required for electrolysis.