Which of the following statements are correct?
(i) The electrolysis of aqueous NaCl produces hydrogen gas at the cathode and chlorine gas at the anode
(ii) The electrolysis of a CuSO4 solution using Pt electrodes causes the liberation of O2 at the anode and the deposition of copper at the cathode
(iii) Oxygen and hydrogen are produced at the anode and cathode during the electrolysis of dilute aqueous solution of H2SO4
(iv) All electrolytic reactions are redox reactions