Question

When an aqueous solution of $\ce{CuCl_2}$ is electrolysed using Pt inert electrodes, the reaction at cathode and anode respectively are

• A. $4 H _{2} O (l) \stackrel{+4 e^{-}}{\longrightarrow} 2 H _{2}( g )+ 4 \overline{ O } H _{2}( aq );\,2 H _{2} O (l) \stackrel{-4 e^-}{\longrightarrow} O _{2}(g)+4 H ^{+}(a q)$
• B. $2 Cu ^{2+}( aq ) \stackrel{+4 e^{-}}{\longrightarrow} 2 Cu ( s ); 2 H _{2} O (l) \stackrel{-4 e^{-}}{\longrightarrow} O _{2}(g)+4 H ^{+}( aq )$
• C. $Cu ^{2+}( aq ) \stackrel{+2 e ^{-}}{\longrightarrow} Cu ( s ) ; 2 Cl ^{-}( aq ) \stackrel{-2 e ^{-}}{\longrightarrow} Cl _{2}(g)$
• D. $2 H _{2} O (l) \stackrel{+2 e^{-}}{\longrightarrow} H _{2}(g)+2 \overline{ O } H ( aq );$ $2 Cl ^{-}( aq ) \stackrel{-2 e ^{-}}{\longrightarrow} Cl _{2}( g )$

Answer 1

Answer: (C)

$CuCl _{2} \longrightarrow Cu ^{2+}(a q)+2 Cl ^{-}(a q)$

$Cl ^{-}$ show oxidation at anode and form $Cl _{2}$ gas.

$2 Cl ^{-} \stackrel{-2 e^{-}}{\longrightarrow } Cl _{2}(g)$

Due to less reactivity, $Cu ^{2+}$ gain electrons and deposited at cathode electrode.

$Cu ^{2+}+2 e^{-} \longrightarrow Cu$