Out of the following matals that cannot be obtained by electrolysis of the aquenous solution of their salts is

Options

A. Ag
B. Mg
C. Cu
D. Al

Answer

B, D

Explanation

Both `Ca^(2+)` and `Mg^(2+)` ions present in hard water will be reduced `2H_(2)O + 2e^(-) to H_(2) + 2OH^(-)`