Question

(b)Write equations for the reactions taking place at the two electrodes during the electrolysis of

(1) Acidified CuSO4 solution with copper electrodes.

(2) Molten PbBr2 with inert electrodes.

[mention clearly the name of the electrode in each case]
​

Answer 1

Answer:

(i) At the anode oxidation reaction takes place.

At anode : Cu−2e

−

→Cu

2+

At cathode redution reaction occurs.

At cathode : Cu

2+

+2e

−

→Cu

Here both copper electrodes are used.

(ii) At anode : Br

−

−e

−

→Br

Br+Br→Br

2

At cathode : Pb

2+

+2e

−

→Pb

Here both anode and cathode are made up of graphite as it is unaffected by bromine vapours

Answer 2

Electrolysis is the flow of electrical current through a molten or aqueous solution.

(1) Acidified CuSO4 solution with copper electrode.

Reaction on Anode: Oxidation takes place here.

Copper is taken as electrode,

Cu » Cu – 2e- = Cu 2+

Reaction on Cathode: Reduction takes place here.

Copper is taken as electrode,

Cu » Cu2+ + 2e- = Cu

(ii) Molten PbBr2 with inert electrodes.

At anode:

Br» Br1- – 1e = Br

Br + Br = 2Br

At cathode :

Pb» Pb1+ + 2e- = Pb

Here both anode and cathode are made up of graphite as it is unaffected by bromine vapours.