CHEM 208 Lecture Notes - Lecture 8: Acid Rain, Catalytic Converter, Scrubbers
Document Summary
When atmospheric carbon dioxide dissolves in water it forms carbonic acid. Co2 (g) + h2o ( ) h2co3 (aq) The acid formed dissociates partially generating small amounts of hydrogen ions. The hydrogen ions formed are responsible for the weakly acidic nature of rain. The acidity (a measure of hydrogen ion concentration) of a solution is conveniently described in terms of ph scale. According to this scale, if: ph < 7: solution is acidic ph > 7: solution is basic ph = 7: solution is neutral. Based on the concentration of carbonic acid and small amounts of other natural acids, the estimated ph of rain (as well as fog, dew and snow) under normal atmospheric conditions should be around 5. 3. Field measurements in many areas, on the other hand, show much lower ph values (4. 1- 4. 5). Higher acidity (lower ph) is due to the reactions of (cid:2)nox and sox present in the atmosphere.
