Which among the following equations represents the reduction reaction taking place in lead accumulator at positive electrode, while it is being used as a source of electrical energy ?

Options

A. `Pb rarr Pb^(2+)`
B. `Pb^(4+) rarr Pb`
C. `Pb^(2+) rarr Pb`
D. `Pb^(4+) rarr Pb^(2+)`

Answer

D

Explanation

The reaction involved for lead accumulator during discharging i.e, when cell is in the use are
At anode : `Pb(s) + HSO_(4)^(-)(aq) rarr PbSO_(4)(s) + H^(+) + 2e^(-)`
At cathode : `PbO_(2)(s)+ 3H^(+) +HSO_(4)^(-)(aq)`
`+2e^(-) rarr PbSO_4(s) + 2H_(2)O(l)`
Overall reaction : `Pb(s) +PbO_(2)(s) + 2H^(+)`
`+2HSO_(4)^(-)(aq) rarr 2PbSO_(4)(s) + 2H_(2)O(l)`