A strong electrolyte and a week electrolyte .

Explanation

### Step-by-Step Solution:

1. **Definition of Electrolytes**:
- Electrolytes are substances that dissociate into ions when dissolved in water. They can be classified into two main categories: strong electrolytes and weak electrolytes.

2. **Strong Electrolytes**:
- A strong electrolyte is a substance that completely dissociates into its ions in an aqueous solution. This means that when a strong electrolyte is dissolved in water, it breaks down entirely into its constituent ions.
- **Example**: Sodium chloride (NaCl) is a strong electrolyte. When dissolved in water, it dissociates as follows:
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