Question
Predict the products of electrolysis obtained at the electrodes in each case when the electrodes used are of platinum.
(i) An aqueous solution of AgNO3.
(ii) An aqueous solution of H2SO4.
Solution
(i)
Reaction in solution
Reaction in solution
AgNO3 ↔ Ag + + NO3–
H2O ↔ H+ + OH–
Reaction at cathode
Ag+ + e– → Ag
Reaction at anode
Due to platinum electrode self of ionization of water will take place
H2O → 2H+ + 1/2O2(g) + 2e–
Hence Ag will deposit at cathode and O2 gas will generate at anode
(ii)
Reaction in solution
H2SO4 ↔ 2H + + SO42–
H2O ↔ H+ + OH–
Reaction at cathode
H+ + e– → ½ H2
Reaction at anode
Due to platinum electrode self of ionization of water will take place
H2O → 2H+ + 1/2O2(g) + 2e–
Hence H2 gas will generate at cathode and O2 gas will generate at anode
