Question

How the acid rain damages the building made up of marble?

Answer 1

• Acid rain results from acids such as sulphuric acid and nitric acid present in polluted air. These acids are formed when oxides of sulphur and nitrogen respectively come in contact with rainwater.
• Due to the presence of a large number of industries, the air of Agra is highly contaminated with the oxides of sulphur and nitrogen.
• These substances can rise very high into the atmosphere where they mix and react with water, oxygen and other chemicals to form more acidic pollutants.
• $\underset{\mathrm{Marble}}{{\mathrm{CaCO}}_3\left(\mathrm{s}\right)}+\underset{\mathrm{Sulphuric}\mathrm{acid}}{H_{2}S{O}_4(\mathrm{l}})\to \underset{\mathrm{Calcium}\mathrm{sulphate}}{{\mathrm{CaSO}}_4\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}+\underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}$
• These pollutants cause acid rain.
• Acid rain reacts with marble (calcium carbonate / ${\mathrm{CaCO}}_3$) and corrodes it. The white colour of the marble changes to yellow.