Which statement is true about the cathode in an electrolytic cell?

Which statement is true about the cathode in an electrolytic cell?

• A. It is the positive electrode where oxidation occurs
• B. It is the negative electrode where reduction occurs
• C. It is the positive electrode where reduction occurs
• D. It is the negative electrode where oxidation occurs

Answer: (B)

In an electrolytic cell, energy from an external power source drives a non-spontaneous redox reaction. Electrons are pushed into the cathode from the power supply, so the cathode becomes the negative electrode. At this negative electrode, species in solution gain electrons, meaning reduction occurs there. The opposite electrode, the anode, is positive and is the site of oxidation. A classic example is electrolysis of molten NaCl: Na+ ions are reduced to Na metal at the cathode, while Cl− ions are oxidized to Cl2 at the anode. So the cathode is the negative electrode where reduction happens.

In an electrolytic cell, energy from an external power source drives a non-spontaneous redox reaction. Electrons are pushed into the cathode from the power supply, so the cathode becomes the negative electrode. At this negative electrode, species in solution gain electrons, meaning reduction occurs there. The opposite electrode, the anode, is positive and is the site of oxidation. A classic example is electrolysis of molten NaCl: Na+ ions are reduced to Na metal at the cathode, while Cl− ions are oxidized to Cl2 at the anode. So the cathode is the negative electrode where reduction happens.