In: Chemistry
One can argue that both nitric oxide and sulfur dioxide are natural, and hence, harmless. Would you agree or disagree with this statement? Explain using the concept of equilibrium and biogeochemical cycles, and discuss their effects on natural waters.
I completely disagree with the statements.
Nitric oxide in the air may convert to nitric acid, which has been implicated in acid rain. However, it is an important source of nutrition for plant life in the form of nitrates. Furthermore, both NO and NO2 participate in ozone layer depletion. Nitric oxide is a small highly diffusible gas and a ubiquitous bioactive molecule.
The SO2 is hygroscopic, when it is in the atmosphere it reacts with humidity and forms sulphuric and sulphurous aerosol acid that is later part of the so-called acid rain. The intensity in the formation of aerosols and the permanence of them in the atmosphere depend on the meteorological conditions and the quantity of catalytic impurities (substances that accelerate the processes) present in the air. But in general, the average time of permanence in the atmosphere is around 3-5 days, so it can be transported to greater distances.
Both the gas increase the acidity of natural waters by converting into acid.
4 NO + O2 + 2 H2O → 4 HNO2
Also,
SO2 (aq) + H2O (l) H2SO3 (aq). This disrupts the balance of acidity and leads to death of fishes etc.