What is formed at the cathode during electrolysis?

• A. Metals and hydrogen
• B. Oxygen gas
• C. Chlorine gas
• D. Hydrogen ions

Answer: (A)

At the cathode, reduction happens—the negatively charged electrode attracts positively charged ions, which gain electrons there. If the electrolyte contains metal ions that can be reduced more easily than hydrogen, those metal ions gain electrons and deposit as metal on the cathode. If no metal ions are easily reduced, water or hydrogen ions (H+) are reduced instead, producing hydrogen gas at the cathode. So the cathode can produce either a metal or hydrogen gas, depending on the solution. That’s why the option metals and hydrogen is the best choice: it covers both possible outcomes you might see at the cathode in different electrolytes. Oxygen or chlorine gases form at the anode, not the cathode, and hydrogen ions are the reactants reduced at the cathode, not the products formed there.