When rain is accompanied by a thunderstorm, the collected rain water will have a pH value

Options

A. slightly lower than that of rain water without thunderstorm
B. slightly higher than that of rain water without thunderstorm
C. uninfluenced by occurrence of thunderstorm
D. which depends on amount of dust in air

Answer

To determine the pH value of rainwater collected during a thunderstorm, we can follow these steps:

### Step 1: Understand the Composition of Rainwater
Rainwater is typically neutral with a pH around 7. However, it can be influenced by various factors, including atmospheric pollutants.

**Hint:** Consider what natural processes might alter the pH of rainwater.

### Step 2: Identify the Effects of Thunderstorms
During thunderstorms, there is an increased occurrence of lightning, which can lead to the formation of nitrogen oxides (NOx). Additionally, sulfur oxides (SOx) can also be present due to industrial emissions.

**Hint:** Think about how lightning and industrial activities contribute to the formation of acids in the atmosphere.

### Step 3: Formation of Acids
The nitrogen oxides and sulfur oxides formed during thunderstorms can dissolve in rainwater to form acids. For example:
- Sulfur dioxide (SO2) can react with water to form sulfurous acid (H2SO3) or further oxidize to sulfuric acid (H2SO4).
- Nitrogen dioxide (NO2) can react with water to form nitric acid (HNO3).

**Hint:** Recall the chemical reactions that produce acids from oxides.

### Step 4: Impact on pH
The presence of these acids in rainwater will lower the pH value, making the rainwater more acidic than normal rainwater, which is generally neutral.

**Hint:** Consider how the addition of acids affects the pH scale.

### Step 5: Conclusion
Therefore, when rain is accompanied by a thunderstorm, the collected rainwater will have a pH value that is slightly lower than that of rainwater without a thunderstorm due to the formation of acids from the dissolved oxides.

**Final Answer:** The collected rainwater will have a pH value slightly lower than that of rainwater without a thunderstorm.