Final answer:
During the electrolysis of molten calcium chloride, calcium ions are reduced at the cathode to form liquid metallic calcium.
Step-by-step explanation:
During the electrolysis of molten calcium chloride, calcium ions are reduced at the cathode. The reduction reaction that occurs can be represented by the following half-equation: Ca2+ + 2e− → Ca(l). This means that calcium ions (Ca2+) gain electrons (2e−) and are reduced to form liquid metallic calcium (Ca(l)).
It is important to note that this process occurs in a liquid state, where the molten calcium chloride conducts electricity, allowing for the movement of ions towards the electrodes. The chloride ions, on the other hand, migrate to the anode where they are oxidized to chlorine gas (Cl2(g)). Thus, the correct answer to what happens at the cathode during the electrolysis of molten calcium chloride is: calcium ions are reduced.