The alkali metals are obtained not by the electrolysis of the aqueous solutions of their salts but by the electrolysis of their molten salts. Explain.

Explanation

The solutions of alkali metal salts contain metal cations, anions, `H^(+)` ions and `OH^(-)` ions. The discharge potential of `H^(+)` ion is lower than that of metal cations. So, on electrolysis of the solutions of alkali metal salts, hydrogen is discharged at the cathode rather than the metal. However, when the molten salts of alkali metals are electrolysed, the metal cation being the only cation present, gets discharged at the cathode.