Question

What is the source of acid rain?

1) Acid rain is from dissolved carbon dioxide.
2) All rain is acid rain because rain has a pH is less than 7.
3) Rain is normally basic, but depending on the weather it can get slightly acidic.
4) All rain is acid rain because rain has a hydronium ion concentration greater than 10-7 M.
5) none of the above

Answer 1

Acid rain is caused by sulfur dioxide, sulfur trioxide, nitrogen oxide, and nitrogen dioxide in the atmosphere, which form sulfuric and nitric acids, lowering the pH of the rainwater to less than 5.

Step-by-step explanation:

The source of acid rain is primarily due to the atmospheric chemicals sulfurous compounds like sulfur dioxide (SO2) and sulfur trioxide (SO3), and nitrogenous compounds such as nitrogen oxide (NO) and nitrogen dioxide (NO2). These oxides react with the water vapor present in the atmosphere to form sulfuric acid and nitric acid, respectively. Normal rainwater is slightly acidic with a pH between 5 and 6 because of the formation of carbonic acid from dissolved carbon dioxide. However, genuine acid rain has a pH of less than 5 and constitutes not only carbonic acid but also sulfuric and nitric acids, which significantly lower the pH of the precipitation.