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)

On electrolysis only in case of $C{a}^{2+}$ salt aqueous solution $H_2$ gas discharge at Cathode.

Case of $Cr$

At cathode : $C{r}^{3+}+2e^{-}⟶Cr$

So, $Cr$ is deposited.

Case of $Ag$ At cathode : $A{g}^{+}+e^{-}⟶Ag$

So, $Ag$ is deposited.

Case of $Cu$

At cathode : $C{u}^{2+}+2e^{-}⟶Cu$

Case of $C{a}^{2+}$

At cathode $:H_{2}O+e^{-}⟶\frac{1}{2}{H}_2+O{H}^{-}$