Stage 1 Chemistry Investigations Folio: Issue Investigation
Acid rain contains relatively high levels of acid-forming chemicals; it usually has a pH
between 2 and 3 compared to normal rain which has a pH of 5. Causes of acid rain
include air pollution such as chemical manufacturing or smelting. Acid rain can have
various effects on the environment but there are solutions that can help reduce the
production of acid rain.
Unpolluted rain has a pH of 5; all rain is slightly acidic with the same acidity of bread,
black coffee and some shampoos. Normal rain is made mostly of carbon dioxide
dissolved in water (CO2 + H2O H2CO3) which produces carbonic acid. The carbonic
acid contributes to the slight acidity in normal rain.
Acid rain usually has a pH of 2, making it as acidic as lemon juice or normal stomach
acid. If severe, it can erode buildings and statues.
Causes of Acid Rain
Things like car exhausts combined with the presence of high temperatures can
contribute to the production of nitrogen oxides.
Nitrogen gas + oxygen gas Nitric Oxide
Nitric oxide + oxygen gas Nitrogen Oxide
Effects of Acid Rain