Products of Electrolysis
- The product of electrolysis produced depends on the nature of material being that is being electrolyzed as well as the type of electrodes that is being used.
- An inert electrode e.g., platinum or gold does not participate in chemicalreaction and acts as a source or sink for electrons.
- Whereas a reactive electrode participates in the electrode reaction.
- It also depends on the different oxidizingas well as reducing species that are present in the electrolytic cell and their standardelectrode potentials.
- Electrolysis of molten NaCl results in the production of sodium metal and Cl2
- Net reactions may be summarized as:
NaCl (aq) --> Na+ (aq) + Cl– (aq)
Cathode: H2O(l) + e– --> ½ H2(g) + OH– (aq)
Anode: Cl– (aq) --> ½ Cl2(g) + e–
NaCl(aq) + H2O(l) --> Na+(aq) + OH–(aq) + ½H2(g) + ½Cl2(g)
Given the standard electrode potentials,
K+/ K = - 2.93V,
Ag+/ Ag = 0.80V,
Hg2+ / Hg = 0.79V
Mg2+ / Mg = - 2.37 V,
Cr3+ / Cr = - 0.74V
Arrange these metals in their increasing order of reducing power.
Lower the reduction potential leads to higher reducing power. The given standard electrode potentials increases in the following order:
K+/ K < Mg2+ / Mg < Cr3+ / Cr < Hg2+ / Hg < Ag+ / Ag.
Hence, reducing power of the given metals increases in the following order:
Ag < Hg < Cr < Mg < K