Chemistry
Give the electrode reactions for formation of
(i) Lead metal and bromine vapours from molten PbBr2 using inert electrodes
(ii) H2 and O2 gas [2:1] from acidified water using inert Pt electrodes.
Answer
(i) Formation of Lead metal and bromine vapours from molten PbBr2 using inert electrodes
At cathode:
Pb2+ + 2e– ⟶ Pb
At anode:
2Br– – 2e– ⟶ Br
Br + Br ⟶ Br2
(ii) Formation of H2 and O2 gas [2:1] from acidified water using inert Pt electrodes.
At cathode:
4H+ + 4e– ⟶ 4H
2H + 2H ⟶ 2H2
At anode:
4OH+ – 4e– ⟶ 4OH
4OH ⟶ 2H2O + O2
Related Questions
Give reasons for the following changes —
(i) pure water a non-electrolyte — becomes an electrolyte on addition of dil. H2SO4
(ii) Blue colour of aq. CuSO4 — turns almost colourless on it's electrolysis using Pt electrodes.
State the reason for difference in product formed at the anode during electrolysis of aq. CuSO4 using :
(i) active electrode — copper anode
(ii) inert electrode — platinum anode.
Starting from aq. copper (II) sulphate solution, give equations for the reactions at the cathode and anode during electrolysis of aq. CuSO4 using active copper electrodes.
With reference to nature of electrodes — name three inert and three active electrodes.