Acid Rain : LUSENET : Introductory Geology, Oswego State : One Thread

On page 123 of our text it states that most acidity in acid rain comes from sulfuric and nitric acid. How does this differ from carbonic acid in the way it reacts to rock minerals?

-- Tina Miller (, March 01, 2001


I just want to make sure people aren't getting confused on this. The term "acid rain" refers to highly acidic precipitation that is the result of pollution. Nitrogen and sulfur compounds in smokestack emissions (especially from things like coal-burning power plants) form nitric and sulfuric acid when they react with water in the atmosphere. What we said in class is that ALL rain, even un-polluted rain, is somewhat acidic because carbon dioxide in the atmosphere (and CO2 is everywhere -- not just downwind of powerplant smokestacks) reacts with water to form carbonic acid. Rain has pHs in the 5-6 range, but "acid rain" has pHs in the 3-5 range (remember 7 on the pH scale is neutral and the numbers on the scale get lower with increasing acidity). So do you think acid rain would react with rocks differently than "regular" rain?

-- Sharon Gabel (, March 01, 2001.

So if I am getting this right, it is all a matter of how much acid is in the rain, to the extent of breakdown in a mineral to how fast it will breakdown? So, I would say that rain, no matter what type, is going to break down rock due to the presence of carbon dioxide. It just all depends on the extent of the acid within the rain. Right?

-- Tina Miller (, March 01, 2001.

That makes sense to me. The more acidic the water, the more aggressively it can attack minerals.

-- S. Gabel (, March 01, 2001.

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