Question

Why does the rain water normally have a Ph of about 5.6 ? When does it become acid rain ?

Answer 1

if th ph of rain is less than 5.6,it turns to be acid rain.

Answer 2

Answer:

Rain water naturally contains CO2 (Carbon dioxide) as H2CO3 (carbonic acid), so it is slightly acidic. However, once different acids are added into rain water (like sulfur dioxide and nitrous dioxide ), the pH will go below 5.6, making it acid rain.

Explanation:

Pure rain water is naturally acidic due to the presence of carbonic acid.  However, the addition of other acids due to pollution and such, makes the rain water more acidic than normal, hence why rain water with many pollutants is considered acid rain.