Suraj Prasad
Last Activity: 10 Years ago
Pure water has a pH of 7.0 (neutral); however, natural, unpolluted rainwater actually has a pH of about 5.6 (acidic).[Recall that pH is a measure of the hydrogen ion (H+) concentration.] The acidity of rainwater comes from the natural presence of three substances (CO2, NO, and SO2) found in the troposphere (the lowest layer of the atmosphere).