There is always a half-equation on the Cathode and another half-equations at the Anode.

Both half equations consists of electrons. Use Simultaneous Equations technique to balance off the electrons and you will end up with the Overall Reaction Equation for electrolysis.

Hope this information helps. =)

(i) Name the ions present in molten copper (II) bromide and the products at the electrodes.

(ii) Write equations, including states symbols, to represent the reaction at the cathode and the anode.

(iii) Finally, write the overall reaction that occurs when molten copper(II) bromide is electrolysed.

(i) ions present: Cu2+, Br-
Products:
at anode: Br2 (g)
at cathode: Cu (s)
(ii) equations:
At anode: Br- (aq) – e- ?Br, 2Br(aq) ? Br2(g)
At cathode: Cu2+ (aq) + 2e- ?Cu(s)
(iii) overall equation: CuBr2 (aq)?Cu(s)+Br2(aq)

For electrolysis of molten NaCl, products are:
@ Cathode: Sodium Metal
@ Anode: Chlorine Gas

For electrolysis of dilute aqueous NaCl, products are:
@ Cathode: Hydrogen Gas
@ Anode: Oxygen Gas

Above products will be liberated/produced when electrolysis are carried out using Inert Electrodes such as Carbon or Platinum electrodes.

Hope you will find the above information useful towards your learning.

To Your Academic Success in Chemistry,
Sean
Master Trainer
Author

Thanks for helping me!