Chemistry
Give scientific reasons :
(i) During electrolysis of molten lead bromide, graphite anode is preferred to other electrodes.
(ii) Electrical conductivity of acetic acid is less in comparison to that of dil. H2SO4 – at a given concentration.
(iii) Electrolysis of molten lead bromide is considered to be a redox reaction.
Answer
(i) As graphite is unaffected by the reactive bromine vapours released at the anode hence, a graphite anode is preferred during the electrolysis of molten lead bromide.
(ii) Dil. H2SO4 is a strong electrolyte and acetic acid is a weak electrolyte. Therefore, dil. H2SO4 allows large amount of electricity to flow through them and are good conductors of electricity whereas acetic acid allows small amount of electricity to flow through them and are poor conductors of electricity. Hence, electrical conductivity of acetic acid is less in comparison to that of dil. H2SO4 – at a given concentration.
(iii) Electrolysis of molten lead bromide involves oxidation and reduction reactions and hence is a redox reaction.
Reduction reaction at cathode:
Pb2+ + 2e- ⟶ Pb
Oxidation reaction at the anode:
Br1- - 1e- ⟶ Br
Br + Br ⟶ Br2
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