(i) Electrolyte - Aqueous solution of nickel sulphate
(ii) Cathode - Cleaned key chain to be electroplated
(iii) Anode - Block of nickel metal
(iv) Reaction at cathode: From the electrolyte, the nickel ions gain electrons to form nickel atoms, that get deposited on the article (key chain) as a layer of nickel:
(v) Reaction at anode: The nickel anode loses electrons to become nickel ions and goes into the electrolyte.