Acid Rain
Nitrogen oxides are produced in all internal combustion engines.
They can form nitric acid, which is not only a strong acid, but also a strongly oxidizing acid.
N2 (g) + O2 (g) 2 NO(g)
2 NO(g) + O2 (g) 2 NO2 (g)
3 NO2 (g) + H2O(l) 2 HNO3 (aq) + NO(g)
(Final step in the
Ostwald process)
These acids are a potentially severe problem in the eastern United States and other parts of the world. The average pH of rain in the eastern U.S. back in 1984 was 4.2. Sweden and Pennsylvania share second place with a pH of 2.7, but the record was in Wheeling, West Virginia where the pH was 1.8. Some areas of California also reach a pH of 1.6. The problems are global in nature.
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