When a lead storage battery is dischargedSO2 is evolvedLead sulphate is consumedLead is formedSulphuric acid is consumed

When a lead storage battery is discharged, the following steps occur:

1. The battery discharging process is essentially a chemical reaction. In a lead-acid battery, this involves lead (Pb), lead dioxide (PbO2), and sulphuric acid (H2SO4).

2. When the battery is in use (i.e., discharging), the lead dioxide (positive plate) and lead (negative plate) react with the sulphuric acid to create lead sulphate (PbSO4), water (H2O), and energy.

3. So, in this process, sulphuric acid (H2SO4) is consumed as it reacts with the lead and lead dioxide to form lead sulphate and water. This reaction releases energy that is used to power the connected device.

4. The formation of lead sulphate from lead and lead dioxide is a reversible reaction. When the battery is recharged, the lead sulphate is converted back into lead, lead dioxide, and sulphuric acid.

5. However, the question seems to have a mistake. SO2 (sulphur dioxide) is not evolved during the discharging of a lead-acid battery. Instead, lead sulphate is formed and sulphuric acid is consumed.

So, to correct the statement: When a lead storage battery is discharged, lead sulphate is formed, and sulphuric acid is consumed.