Question

How are acid rains produced?

Answer 1

Acid rain:

• Acid rain occurs mainly due to the formation of mineral acids like Sulphuric acid, and Nitric acid due to the reaction between rainwater and respective oxides of these nonmetals.
• As these oxides are present in the atmosphere, where these oxides react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.
• The oxides of Sulphur and Nitrogen are present in the atmosphere due to the burning of Sulphur and the internal combustion of vehicles.

The following reactions occur during acid rain:

• Formation of Sulphuric acid:

$\underset{\mathrm{Sulphur}\mathrm{trioxide}}{{\mathrm{SO}}_3\left(\mathrm{g}\right)}+\underset{\mathrm{Water}\mathrm{vapours}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)}\to \underset{\mathrm{Sulphuric}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{l}\right)}$

• Formation of Nitric acid:

$\underset{\mathrm{Nitrogen}\mathrm{dioxide}}{4{\mathrm{NO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Water}\mathrm{vapours}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{Nitric}\mathrm{acid}}{4{\mathrm{HNO}}_3\left(\mathrm{l}\right)}$