a. The half-equation for electrolysis of molten
calcium oxide is:
2O2- (l) → O2 (g) + 4e-
b. The half-equation for electrolysis of molten
potassium bromide is:
K+ (l) + e- → K (s)
How can you write their half equations?
The process at the positive electrode in the electrolysis of molten calcium oxide.
At the positive electrode, oxidation occurs. The oxygen in calcium oxide (CaO) loses electrons to form oxygen gas (O2). The half-equation for this process is:
2O2- (l) → O2 (g) + 4e-
b) The process at the negative electrode in the electrolysis of molten potassium bromide.
At the negative electrode, reduction occurs. The potassium ions (K+) in potassium bromide (KBr) gain electrons to form potassium metal (K). The half-equation for this process is:
K+ (l) + e- → K (s)