Yes, natural, unpolluted rainwater is slightly acidic.
While pure water has a neutral pH of 7.0, rainwater typically has a pH of around 5.6. This acidity is primarily due to the absorption of atmospheric carbon dioxide (CO2), which reacts with water to form carbonic acid (H2CO3).
Here's a breakdown:
- Pure Water: pH 7.0 (Neutral)
- Natural Rainwater: pH ~5.6 (Slightly Acidic)
The natural acidity of rainwater is important to understand because it forms a baseline against which to measure the impact of pollution, such as acid rain caused by industrial emissions. Acid rain has a much lower pH than natural rainwater.
