pH value of acid rain
Acid rain is defined as any form of precipitation with acidic components, such as sulfuric or nitric acid, that fall to the ground from the atmosphere. The pH value of acid rain is typically below 5.6, which is the pH of pure water. However, it can range from around 4 to 2, depending on the concentration of acidic pollutants present in the rain.

Causes of low pH in acid rain
The main reason for the low pH of acid rain is the presence of pollutants like sulfur dioxide (SO2) and nitrogen oxides (NOx) in the atmosphere. These gases can react with water vapor and other chemicals in the air to form sulfuric and nitric acids, which are then carried by wind currents and deposited as acid rain.

Effects of low pH in acid rain
The low pH of acid rain can have detrimental effects on the environment, including:
- Damage to aquatic ecosystems: Acid rain can lower the pH of bodies of water, making them too acidic for many aquatic organisms to survive.
- Harm to vegetation: Acid rain can damage plant leaves and inhibit their growth by disrupting nutrient uptake and damaging cell membranes.
- Corrosion of buildings and infrastructure: Acid rain can accelerate the deterioration of buildings, monuments, and infrastructure made of materials like limestone and marble.

Monitoring and prevention
Monitoring the pH of rainwater is crucial in understanding the extent of acid rain pollution. Efforts to reduce emissions of sulfur dioxide and nitrogen oxides, such as implementing stricter environmental regulations and using cleaner energy sources, can help prevent the formation of acid rain and mitigate its harmful effects on the environment.

Normal, clean rain has a pH value of between 5.0 and 5.5, which is slightlyacidic. However, when rain combines with sulfur dioxide or nitrogen oxides—produced from power plants and automobiles—the rain becomes much more acidic. Typical acid rain has a pH value of 4.0.