The electrode reactions for charging of a leas storage battery are :
`PbSO_(4) + 2e^(-) = Pb + SO_(4)^(2-)`
`PbSO_(4) + 2H_(2)O = PbO_(2) + SO_(4)^(2-) + 4H^(+) 2e^(-)`
The electrolyte in the battery is an aqueous solution of sulphuric acid. Before charging, the specific gravity of the liquid was found to be 1.11 (15.7% `H_(2)SO_(4)` by weight). After charging for 100 hours, the sp. gr. of the liquid was found to be 1.28 (36.9% `H_(2)SO_(4)` by wr.). If the battery contained two litres of the liquid, calculate the average current used for charging the battery.
NB. `(e^(-))` denotes electrons. Assume that the volume of the battery liquid remained constant during charging. 1 faraday = 96500 coulombs.

Explanation

To calculate the average current used for charging the lead storage battery, we will follow these steps:

### Step 1: Calculate the mass of H₂SO₄ before charging
Given:
- Specific gravity before charging = 1.11
- Percentage of H₂SO₄ by weight = 15.7%
- Volume of the liquid = 2 liters = 2000 mL

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