What is Acid rain ? What are its harmful effects ?

Explanation

### Step-by-Step Solution:

**Step 1: Definition of Acid Rain**
Acid rain is defined as precipitation that has a lower pH than normal rainwater, typically due to the presence of sulfur dioxide (SO2), nitrogen oxides (NO2), and carbon dioxide (CO2) in the atmosphere. These gases are primarily released from the combustion of fossil fuels.

**Step 2: Formation of Acid Rain**
When rainwater comes into contact with these gases, it reacts with them to form acids, primarily sulfuric acid (H2SO4) and nitric acid (HNO3). This process occurs in the atmosphere, leading to the formation of acid rain.

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