What does electrolysis do to an ionic compound?

• A. Separates into the elements that form it
• B. Combines elements
• C. Dissolves into ions
• D. Changes to a new compound

Answer: (A)

Electrolysis uses electrical energy to break apart an ionic compound that is molten or dissolved. When the current is applied, the ions are driven to the electrodes and each ion gains or loses electrons at the surface, turning into neutral atoms or simple molecules. This process decomposes the compound into its constituent elements (or their simplest substances), rather than forming a new compound or simply staying dissolved. For example, molten salt like NaCl splits into sodium metal at one electrode and chlorine gas at the other. So the key idea is that electrolysis decomposes an ionic compound into the elements that make it up.