What is the general role of the cathode in electrolysis?

• A. Where oxidation occurs
• B. Where reduction occurs
• C. Where gas is produced
• D. Where the current enters the cell

Answer: (B)

The main idea here is that the cathode is the site of reduction. In electrolysis, the external power source pushes electrons into the cathode, making it negatively charged. Positive ions in the electrolyte move to the cathode and gain electrons, becoming neutral atoms or molecules. This is how metal ions can deposit as a layer on the cathode or how hydrogen gas can be produced from H+ in acidic solutions. The other electrode is where oxidation happens, so the cathode’s defining role is reduction, not merely gas production or the current’s entry point.