What is the chemical formula for acid raid?

Will you show the original reactants, and not just the balanced formula?

1 Answer
Mar 11, 2016

2SO2+O2+2H2O2H2SO4

4NO2+O2+2H2O4HNO3

Explanation:

Pure rainwater is already acidic due to carbon dioxide (CO2) in the air dissolving in the rainwater and reacting according to the following equation.

H2O+CO2H2CO3

Acid rain is caused additionally by having large amounts of sulfur dioxide (SO2) and nitrogen oxides (NOx) from the atmosphere dissolve into the rainwater.

Sulfur dioxide is produced primarily from burning of fossil fuels that contains sulfur. It gets oxidized by molecular oxygen present in air to produce sulfur trioxide (SO3), according to the following reaction.

2SO2+O22SO3

The sulfur trioxide produced then dissolves in the rainwater.

SO3+H2OH2SO4

The overall reaction is given by combining the two steps.

2SO2+O2+2H2O2H2SO4

Nitrogen dioxide results from combustion using air (which 99% is made up of N2 and O2) as oxidants. It reacts in water to form a equimolar nitrous (HNO2) and nitric acid (HNO3) solution.

2NO2+H2OHNO2+HNO3

However, nitrous acid decomposes rapidly to regenerate nitrogen dioxide and water, while at the same time producing nitric oxide (NO).

2HNO2NO+NO2+H2O

The nitric oxide produced can be oxidized by atmospheric oxygen back into nitrogen dioxide, although this happens at a relatively slower rate.

2NO+O22NO2

So when we combine the 3 reactions, the overall equation is

4NO2+O2+2H2O4HNO3

All the acids produced in the above reaction will dissociate in water to give H3O+, which is why the pH decreases.

H2CO3+H2OHCO3+H3O+

HNO3+H2ONO3+H3O+

H2SO4+H2OHSO4+H3O+