Class 12 Chemistry Electrochemistry Products of Electrolysis

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
    Net reaction:
    NaCl(aq) + H2O(l) --> Na+(aq) + OH(aq) + ½H2(g) + ½Cl2(g)

Problem:

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.

 

Solution:

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

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