Why is ordinary water a good conductor of electricity?

Explanation

### Step-by-Step Solution:

1. **Understanding Ordinary Water**: Ordinary water, such as tap water, is often found to be a good conductor of electricity. This is an important observation that leads us to explore the reasons behind it.

2. **Presence of Impurities**: The key reason ordinary water conducts electricity well is due to the presence of impurities, particularly salts. Common table salt (sodium chloride, NaCl) is often dissolved in tap water.

3. **Dissociation of Salt**: When salt dissolves in water, it dissociates into its constituent ions. For sodium chloride, it separates into sodium ions (Na⁺) and chloride ions (Cl⁻).

...