why is it not possible to obtain Na metal by electrolysis of its aqueous solution ?

Asked by  | 24th Jan, 2012, 09:08: PM

Expert Answer:

Sodium can be obtained by the electrolysis of molten sodium chloride .
2 NaCl(l) ?  2 Na(l) + Cl2(g)
Electrolyses in aqueous solution are generally more complicated than in molten salts, because in aqueous solutions there can be competing reactions at the anode and cathode.

Two processes that can always occur in aqueous solution are the reduction and oxidation of water itself.

From a consideration of oxidation potentials alone, we would predict that the oxidation of water would predominate, since it has the lower oxidation potential. In fact in concentrated solutions of NaCl, the oxidation of chloride predominates, because the overvoltage for the formation of  O2(g) is much higher than that of Cl2(g).

Answered by  | 25th Jan, 2012, 11:08: AM

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