Final answer:
For a molten electrolytic cell, such as one used for the electrolysis of molten NaCl, iron cathodes and carbon anodes are typically required, due to their conductivity and durability under the conditions of the reaction.
Step-by-step explanation:
The type of electrode needed for a molten electrolytic cell depends on the specific chemical reaction taking place within the cell. In the instance of molten sodium chloride (NaCl) electrolysis, commonly used in the Downs process for production of sodium and chlorine, iron cathodes and carbon anodes are typically utilized. The iron cathode facilitates the reduction of sodium ions to liquid sodium metal, while the carbon anode aids in the oxidation of chloride ions to chlorine gas.
Iron is chosen as a cathode material because it is a good electrical conductor and reacts well with the sodium ions without corroding. Carbon, often in the form of graphite, is used as an anode for its high melting point and conductivity, essential qualities enabling it to endure the harsh conditions and the formation of chlorine gas in the electrolytic cell.