Final answer:
The two electrodes used for flame rectification are the flame sensor and the igniter. These components work together to detect the presence of a flame in heating systems, ensuring correct operation and safety.
Step-by-step explanation:
The two electrodes used for flame rectification are a flame sensor and an igniter. Flame rectification is a process used in heating systems to confirm the presence of a flame. When the burner is on, the flame sensor and igniter act as electrodes that conduct a small current. This current is rectified, or converted from AC to DC, by the flame's ionization, thus confirming the flame's presence. If no flame is detected, the system will shut down for safety.
The sensor typically acts as the cathode where reduction occurs, while the igniter, which may also serve as the sparking device to ignite the flame, serves as the anode where oxidation occurs. This setup allows the system to detect a flame effectively and respond properly to maintain safe operation.
It should be noted that in the context of electrochemistry, reference electrodes such as the silver-silver chloride electrode and the saturated calomel electrode are used for different purposes. They serve as stable references against which the potentials of other electrodes can be measured. However, they are not directly related to the process of flame rectification.