During the electrolysis of molten calcium chloride, what occurs at the anode?

• A. Chloride ions are oxidized to chlorine gas.
• B. Calcium ions are reduced to calcium metal.
• C. Chloride ions are reduced to chloride gas.
• D. Calcium ions are oxidized to calcium gas.

Answer: (A)

Verified step by step guidance

1. Identify the species present in molten calcium chloride: Ca^{2+} ions and Cl^{-} ions.
2. Recall that during electrolysis, oxidation occurs at the anode and reduction occurs at the cathode.
3. Determine which species will be oxidized at the anode by comparing their tendencies to lose electrons: chloride ions (Cl^{-}) or calcium ions (Ca^{2+}).
4. Recognize that chloride ions (Cl^{-}) lose electrons to form chlorine gas (Cl_{2}) at the anode, which is an oxidation process: 2Cl^{-} \rightarrow Cl_{2} + 2e^{-}.
5. Conclude that at the anode, chloride ions are oxidized to chlorine gas, while calcium ions are reduced at the cathode.