In the electrolysis of molten potassium bromide (K2Br), the compound dissociates into its constituent ions. When potassium bromide is in the molten state, it conducts electricity, and the following ions are present:
Potassium ions (K+): Each potassium atom loses one electron and forms a positively charged ion. The symbol for a potassium ion is K+.
Bromide ions (Br-): Each bromide atom gains one electron and forms a negatively charged ion. The symbol for a bromide ion is Br-.
During the electrolysis process, when an electric current is passed through the molten potassium bromide, positive potassium ions (K+) are attracted to the negative electrode (cathode) and gain electrons, getting reduced to form potassium metal (K). At the same time, negative bromide ions (Br-) are attracted to the positive electrode (anode) and lose electrons, getting oxidized to form bromine gas (Br2).
So, in summary, the ions present in the electrolysis of molten potassium bromide are potassium ions (K+) and bromide ions (Br-).