Products of electrolysis depend on the nature of material being electrolyzed and the type of electrodes being used. If the electrode is inert (e.g., platinum or gold), it does not participate in the chemical reaction and acts only as source or sink for electrons. On the other hand, if the electrode is reactive, it participates in the electrode reaction. Thus, the products of electrolysis may be different for reactive and inert electrodes. The products of electrolysis depend on the different oxidizing and reducing species present in the electrolytic cell and their standard electrode potentials. Moreover, some of the electrochemical processes although feasible, are so slow kinetically that at lower voltages these do not seem to take place and extra potential (called overpotential) has to be applied, which makes such process more difficult to occur.

A concentrated solution of NaCl is electrolysed using inert electrodes. What are the products of electrolysis respectively at anode and cathode?

Cl₂ and H₂

NaCl solution using inert electrodes

NaCl ⇌ Na⁺ + Cl^-

H₂O ⇌ H⁺ + OH^-

At anode: 2Cl^- → Cl₂ + 2e^-

At cathode: 2H⁺ + 2e^- → H₂

Na⁺ interacts whith OH^- to form NaOH. So, pH of solution increases during electrolysis.