What is a primary cell? Give an example.

Explanation

**Step-by-Step Solution:**

1. **Definition of Primary Cell:**
A primary cell is an electrochemical cell in which the chemical reactions that generate electrical energy occur only once. After the reactants are consumed, the cell cannot be recharged or reused.

2. **Characteristics of Primary Cells:**
- The redox (reduction-oxidation) reactions in primary cells happen only once.
- Once the reactants are depleted, the cell is considered "dead" and cannot be restored to its original state.
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