Final answer:
The cathode reaction is the reduction of hydrogen ions to hydrogen gas, and the anode reaction is the oxidation of fluoride ions to fluorine gas in the electrolysis of molten potassium fluoride and hydrogen fluoride.
Step-by-step explanation:
The question asks about the cathode and anode reactions during the electrolysis of molten potassium fluoride (KF) and hydrogen fluoride (HF). The correct answer to this is: Cathode: Reduction of hydrogen ions; Anode: Oxidation of fluoride ions. It is important to remember that in electrolysis, the anode is the electrode where oxidation occurs, and the cathode is the electrode where reduction occurs. Additionally, electrode potentials for molten salts can differ significantly from those for aqueous solutions.
During electrolysis of potassium fluoride (KF) and hydrogen fluoride (HF), the reaction at the cathode involves the reduction of hydrogen ions (H+) to hydrogen gas (H2), which can be represented as 2H+ + 2e- → H2(g). At the anode, oxidation of fluoride ions (F-) occurs, forming fluorine gas (F2), represented as 2F- - 2e- → F2(g).
This electrolytic process is used for the industrial production of fluorine gas, where it is crucial to keep the produced gases separated to prevent explosion.