What is acid rain? Also give two ill effects of acid rain.

Explanation

### Step-by-Step Solution:

1. **Definition of Acid Rain**:
Acid rain is a type of precipitation that has a lower pH than normal rainwater, which is typically around 6. It occurs when certain pollutants in the atmosphere, primarily nitrogen dioxide (NO2) and sulfur dioxide (SO2), react with water vapor.

- **Chemical Reactions**:
- Nitrogen dioxide reacts with water vapor to form nitric acid (HNO3).
- Sulfur dioxide reacts with water vapor to form sulfuric acid (H2SO4).
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