In standard cell notation, which side corresponds to the anode?

• A. The left side
• B. The right side
• C. The middle
• D. The salt bridge

Answer: (A)

The left side is the anode. In standard cell notation, oxidation occurs at the anode and electrons flow from that electrode to the cathode through the external circuit, so the electrode where oxidation happens is written on the left and the reduction occurs on the right. The vertical bars separate phases, and the middle region represents the salt bridge or passage between solutions, not an electrode. For example, in a zinc-cathode cell written as Zn | Zn2+ (aq) || Cu2+ (aq) | Cu, the zinc electrode on the left is the anode.