(i) An aqueous solution of $$AgNO_{3}$$ with silver electrodes.At cathode: Silver ions have lower discharge potential than hydrogen ions. Hence, silver ions will be deposited in preference to hydrogen ions.At anode: Silver anode will dissolve to form silver ions in the solution.$$\\displaystyle Ag \\rightarrow Ag^+ + e^-$$(ii) An aqueous solution of $$AgNO_{3}$$ with platinum electrodes.At cathode: Silver ions have lower discharge potential than hydrogen ions. Hence, silver ions will be deposited in preference to hydrogen ions.At anode: Hydroxide ions having lower discharge potential will be discharged in preference to nitrate ions. Hydroxide ions will decompose to give oxygen.$$\\displaystyle 4OH^- (aq) \\rightarrow 2H_2O(l) +O_2(g) + 4e^-$$(iii) A dilute solution of $$H_{2}SO_{4}$$ with platinum electrodes.At cathode: $$\\displaystyle  2H^+ + 2e^- \\rightarrow H_2(g)$$At anode: Hydroxide ions having lower discharge potential will be discharged in preference to sulphate ions. Hydroxide ions will decompose to give oxygen.$$\\displaystyle 4OH^- (aq) \\rightarrow 2H_2O(l) +O_2(g) + 4e^-$$(iv) An aqueous solution of $$CuCl_{2}$$  with platinum electrodesAt cathode: Cupric ions will be reduced in preference to protons$$\\displaystyle Cu^{2+} + 2e^- \\rightarrow Cu$$At anode: Chloride ions will be oxidized in preference to hydroxide ions$$\\displaystyle 2Cl^- \\rightarrow Cl_2 + 2e^-$$