The D And F Block Elements Ques 60

60. When $CuSO_4$ is electrolysed using platinum electrodes,

[1993]

(a) Copper is liberated at cathode, sulphur at anode

(b) Copper is liberated at cathode, oxygen at anode

(c) Sulphur is liberated at cathode, oxygen at anode

(d) Oxygen is liberated at cathode, copper at anode

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Solution:

  1. (b) $CuSO_4 \rightarrow Cu^{2+}+SO_4^{2-}$;

$ H_2 O \rightarrow H^{+}+OH^{-} $

At cathode: $Cu^{2+}+2 e^{-} \longrightarrow Cu$

At anode : $4 OH^{-} \longrightarrow 2 H_2 O+O_2+4 e^{-}$