What takes place at the cathode during electrolysis?

Analyze the question: It asks what happens at the cathode, the negative electrode, during electrolysis.

Concept:

• The cathode is the negative electrode. It attracts cations (positive ions).
• The anode is the positive electrode. It attracts anions (negative ions).
• Reduction happens at the cathode, where ions gain electrons. Oxidation happens at the anode, where ions lose electrons. Remember OIL RIG: Oxidation Is Loss, Reduction Is Gain.
• When an ion gains or loses electrons to become a neutral atom or molecule, we say it is discharged.

Step-by-step check of the options:

• A. Anions lose electrons: Anions do lose electrons, but they do so at the anode, not the cathode. ✗
• B. Anions are oxidized: Again, this happens at the anode. ✗
• C. Cations are oxidized: Cations gain electrons at the cathode, so they are reduced, not oxidized. ✗
• D. Cations are discharged: Cations migrate to the cathode, gain electrons and become neutral atoms. For example, Cu²⁺ + 2e⁻ → Cu, or 2H⁺ + 2e⁻ → H₂. ✓

Tip: Remember "CAT has Cations" (the cathode attracts cations) and "AN OX" (anode is where oxidation occurs). Also, "RED CAT": reduction occurs at the cathode.