Acid rain is due to
oxides of nitrogen
oxides of sulphur
methane present in air
Select the correct option.

Options

A. I and II
B. II and III
C. I and III
D. All of these

Answer

To determine the cause of acid rain, we need to analyze the options provided: oxides of nitrogen, oxides of sulfur, and methane present in the air.

### Step-by-Step Solution:

1. **Understanding Acid Rain**:
- Acid rain refers to precipitation that has a lower pH than normal rainwater. Normal rainwater has a pH of about 5, while acid rain has a pH of around 4 or lower.

2. **Identifying the Components**:
- **Oxides of Nitrogen**: These include nitrogen monoxide (NO) and nitrogen dioxide (NO2).
- **Oxides of Sulfur**: These primarily include sulfur dioxide (SO2) and sulfur trioxide (SO3).
- **Methane (CH4)**: This is a hydrocarbon gas that does not contribute to acid rain.

3. **Chemical Reactions**:
- When sulfur dioxide (SO2) reacts with water vapor in the atmosphere, it forms sulfuric acid (H2SO4):
\[ SO_2 + H_2O \rightarrow H_2SO_4 \]
- When nitrogen dioxide (NO2) reacts with water, it forms nitric acid (HNO3):
\[ NO_2 + H_2O \rightarrow HNO_3 \]

4. **Conclusion on Acid Rain Formation**:
- Both sulfuric acid and nitric acid contribute to the acidity of rainwater, which leads to acid rain. Therefore, acid rain is primarily due to the presence of oxides of nitrogen and oxides of sulfur.

5. **Eliminating Incorrect Options**:
- Methane does not form acids when reacting with water; instead, it produces carbon dioxide and water. Thus, it does not contribute to acid rain.

6. **Final Answer**:
- The correct options that cause acid rain are oxides of nitrogen and oxides of sulfur. Therefore, the correct answer is:
- **Option 1: Oxides of nitrogen and oxides of sulfur**.