During charging of lead storage bttery, the reaction occurring at the cathode is:-

Options

A. `Pb^(2+)+2etoPb`
B. `PbtoPb^(2+)+2e`
C. `PbSO_(4)+2H_(2)OtoPbO_(2)+4H^(+)+SO_(4)^(2-)+2e^(-)`
D. `Pb^(2+)+SO_(4)^(2-)toPbSO_(4)`

Explanation

To determine the reaction occurring at the cathode during the charging of a lead storage battery, we need to understand the chemistry involved in the lead-acid battery system.

### Step-by-Step Solution:

1. **Understanding the Lead Storage Battery**:
- A lead storage battery (also known as a lead-acid battery) consists of lead dioxide (PbO2) as the positive electrode (cathode during discharge) and sponge lead (Pb) as the negative electrode (anode during discharge). The electrolyte is usually sulfuric acid (H2SO4).

2. **Charging Process**:
- During charging, the battery is supplied with electrical energy, which reverses the chemical reactions that occur during discharge.

3. **Identifying the Cathode Reaction**:
- In a lead-acid battery, during discharge, the cathode reaction involves the reduction of lead dioxide (PbO2) to lead sulfate (PbSO4).
- However, during charging, the reverse reaction occurs at the cathode.

4. **Cathode Reaction During Charging**:
- The reaction at the cathode during charging can be represented as:
\[ PbSO_4 + 2e^- + 2H_2O \rightarrow PbO_2 + H_2SO_4 + 2H^+ \]
- This indicates that lead sulfate (PbSO4) is being converted back into lead dioxide (PbO2) and sulfuric acid (H2SO4).

5. **Final Answer**:
- Therefore, the reaction occurring at the cathode during the charging of a lead storage battery is the conversion of lead sulfate back to lead dioxide.