Buffalo Business Daily

What chemical changes take place in the formation of acid rain?

Help. Please. Now, please keep in mind that I need the chemical changes that take place in the formation of acid rain and not what it is. Thanks.

Public Comments

1. Acidity is measured using a scale called the pH scale. This scale goes from 0 to 14. 0 is the most acidic and 14 is the most alkaline (opposite of acidic). Something with a pH value of 7, we call neutral, this means that it is neither acidic nor alkaline. Very strong acids will burn if they touch your skin and can even destroy metals. Acid rain is much, much weaker than this, never acidic enough to burn your skin. Rain is always slightly acidic because it mixes with naturally occurring oxides in the air. Unpolluted rain would have a pH value of between 5 and 6. When the air becomes more polluted with nitrogen oxides and sulphur dioxide the acidity can increase to a pH value of 4. Some rain has even been recorded as being pH2. Vinegar has a pH value of 2.2 and lemon juice has a value of pH2.3. Even the strongest recorded acid rain is only about as acidic as lemon juice or vinegar and we know that these don't harm us - so why do we worry about acid rain?
2. The main ingredient in acid rain is SO2 or SO3. These gases are emitted into the as a by product of burning fossil fuels. These gases the undergo the following reactions with water (rain) to form sulphuric and sulphurous acid SO3 +H2O = H2SO4 SO2 +H2O = H2SO3 From memory these are the main 2. Nitrous oxides and CO2 will follow similar reactions but I don't think that the effect is as great
3. Oxides of nitrogen (NOx) and Sulphur (SOx) where x=1,2 or 3 are responsible for acid rain. SO2 and NOx are are pollutants released by automobiles and chemical industries. Formation of SO2 and NO2 S (fuel) +2 (from air)-------> SO2 N2+O2------> NO 2NO + O2 ----->NO2 formation of hydrogen peroxide in air: volatile organic compounds + H2O (in air) -----> H2O2 formation of acids; SO2 +H2O2 (in air) ----> H2SO4 SO2 + 2OH. (radical in air) -------> H2SO4 NO2 + OH. (Oh radicals from air) -------> HNO3 The oxides reacts with hydrogen peroxides and ozone present in air to form acids. Thses acids are captured by rain drops and falls in teh earth as acid rain.