Question
Sodium metal cannot be obtained by the electrolysis of aqueous sodium chloride solution.
Solution
The reduction potential values of sodium and water - 2.71 V and - 0.83 V respectively.
Na+(aq) + e → Na(s) E° = –2.71V
2H2O(l) + 2e → H2(g) + 20H– E° = – 0.83 V
Thus Na+ has less tendency to change into a metal compared to H2O which has greater tendency to change into H2 gas. Therefore, H2O accepts electrons preferentially than Na+ in the electrolysis of aqueous chloride. Therefore, metal is not produced.
