In a lead storag battery, Pb (anode) and `PbO_(2)` (cathode) are used. Concentrated `H_(2)SO_(4)` is used as electrolyte. The battery holds 3.5 litre acid with it . In the discharge process, the density of acid fell from 1.294 to 1.139 g/mL. The sulphuric acid of density `1.294" g mL"^(-1)` is 39 % by mass and that of density 1.139 g/mL is 20% by mass.
Which of the following takes place in discharge process at anode ?

Options

A. `PbO_(2)+4H^(+)+SO_(4)^(2-) +2e^(-) rarr PbSO_(4)+2H_(2)O`
B. `PbSO_(4)+2H_(2)O rarr PBO_(2)+4H^(+)+SO_(4)^(2-) +2e^(-)`
C. `Pb+SO_(4)^(2-) rarr PbSO_(4)+2e^(-)`
D. `PbSO_(4) +2e^(-) rarr Pb+SO_(4)^(2-)`

Answer

C