Question

Of the following, the metals that cannot be obtained by electrolysis of the aqueous solution of their salts are ________________.

• A. $Ag$
• B. $Mg$
• C. $Cu$
• D. $Al$
• E. $Cr$

Answer 1

Answer: (B), (D)

$Mg$
$Al$

Magnesium and aluminium lie above hydrogen in electrochemical series. Their standard reduction potentials are lower than that of hydrogen. When their salts are electrolyzed in aqueous solutions, hydrogen gas is liberated at the cathode.