Why does acid rain corrode concrete structures?

Explanation

### Step-by-Step Solution:

1. **Understanding Acid Rain**: Acid rain is precipitation that has a lower pH than normal rainwater, typically due to the presence of sulfuric and nitric acids formed from air pollutants.

2. **Composition of Concrete**: Concrete is primarily made up of cement, water, and aggregates. One of the key components in cement is calcium compounds, such as calcium silicate.

3. **Chemical Reaction**: When acid rain falls on concrete, the acids react with the calcium compounds present in the concrete. This reaction can lead to the dissolution of these compounds.

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