Question

Give reason for the following :

Electrolysis of molten lead bromide is considered a reaction in which oxidation and reduction i.e., a redox reaction occurs.

Answer 1

• Electrolysis of molten lead bromide is written as :
  ${\mathrm{PbBr}}_2\left(\mathrm{l}\right)\stackrel{\mathrm{electric}\mathrm{current}}{\to }\mathrm{Pb}\left(\mathrm{s}\right)+{{\mathrm{Br}}_2}_{}\left(\mathrm{l}\right)$
• Reaction at the cathode :
  ${\mathrm{Pb}}^{2+}\left(\mathrm{l}\right)+2{\mathrm{e}}^{-}\to \mathrm{Pb}\left(\mathrm{s}\right)$…..here ${\mathrm{Pb}}^{2+}$ is gaining electron, so it is getting reduced
• Reaction at the anode :
  $2{\mathrm{Br}}^{-}\left(\mathrm{l}\right)-2{\mathrm{e}}^{-}\to {\mathrm{Br}}_2\left(\mathrm{l}\right)$…. here ${\mathrm{Br}}^{-}$ is loosing electrons , so it is getting oxidised.
• The reaction in which oxidation, as well as reduction, takes place is called a redox reaction.
• Hence, the electrolysis of molten lead bromide is a redox reaction.