During electrolysis, positive ions in the liquid are reduced at the cathode to form what?

• A. Metals or hydrogen
• B. Oxygen
• C. Carbon
• D. Nitrogen

Answer: (A)

At the cathode reduction happens. Positive ions (cations) move to the negatively charged electrode and gain electrons, becoming neutral. If the ion is a metal ion, it is reduced to a metal atom. If the ion is hydrogen (H+), it gains electrons to form hydrogen gas. That’s why the products you can get at the cathode are metals or hydrogen, depending on which ions are present in the solution. Oxygen forms at the anode, not the cathode, and carbon or nitrogen aren’t produced in this situation.