During the discharge of a lead storage battery, the density of sulphuric acid fell from `1.294` to `1.139 g mL^(-1). H_(2)SO_(4)` of density `1.294 gmL^(-1)` is `39%` and that of density `1.139 gmL^(-1)` is `20%` bu weight. The battery holds `3.5L` of acid and the volume practially remains constant during dicharge. calculate reactions are.
`Pb+SO_(4)^(2-)rarr PbSO_(4) +2e^(-)` (charging)
`PbO_(2) +4H^(+) +SO_(4)^(2-) +2e^(-) rarr PbSO_(4)+2H_(2)O` (discharging)

Explanation

For 1.0 L `H_2SO_4`:
Initial mass of `H_2SO_4=1294xx39/100=504.66g,` Final mass of `H_2SO_4=1139xx20/100=227.80g`
`implies H_2SO_4` Consumed/litres `=504.66-227.80=276 g`
`implies` Total `H_2SO_4` used up `=276.86xx3.5=969.01 g=(969.01)/(98) m ol= 9.888 m ol`
Q 1 mole of `H_2SO_4` is associated with transfer of .0 mole of electrons, total of 9.888 mole of electrone tranfer has occured.
Ampere-hour `=(9.888xx96500)/(3600)=2.65Ah`