Question

The metal that cannot be obtained by electrolysis of an aqueous solution of its salts is

• A. $Ag$
• B. $Ca$
• C. $Cu$
• D. $Cr$

Answer 1

Answer: (B)

$Ca$

Answer 2

On electrolysis only in case of $Ca ^{2+}$ salt aqueous solution $H _{2}$ gas discharge at Cathode. Case of $Cr$ At cathode : $Cr ^{3+}+2 e ^{-} \longrightarrow Cr$ So, $Cr$ is deposited. Case of $Ag$ At cathode : $Ag ^{+}+ e ^{-} \longrightarrow Ag$ So, $Ag$ is deposited. Case of $Cu$ At cathode : $Cu ^{2+}+2 e ^{-} \longrightarrow Cu$ Case of $Ca ^{2+}$ At cathode $: H _{2} O + e ^{-} \longrightarrow \frac{1}{2} H _{2}+ OH ^{-}$