Acid Rain - Causes and Effects - UNSOLVED PRACTICE SET

Q7. Write the chemical reactions showing the formation of acid rain from SO₂ and NOₓ in the atmosphere.

Q8. Why is the pH of normal rainwater slightly acidic (around 5.6) even without pollution?

Q9. Explain how acid rain damages marble monuments like the Taj Mahal. Write the relevant chemical equation.

Q10. What is dry deposition? How does it differ from wet deposition (acid rain)?

Q11. Your school is located near an industrial area in Jharkhand. The students notice that the leaves of nearby trees have yellow spots and the soil pH is decreasing. Explain these observations.

Q12. Why are aquatic ecosystems particularly vulnerable to acid rain? What happens to fish populations in acidified lakes?

Q13. Discuss the formation and chemistry of acid rain:

(a) Sources of SO₂ and NOₓ — natural and anthropogenic

(b) Atmospheric reactions converting SO₂ to H₂SO₄ and NOₓ to HNO₃

(c) The role of oxidants (OH radicals, H₂O₂, O₃) in these transformations

(d) Wet deposition (acid rain, snow, fog) vs. dry deposition (acidic gases and particles)

(e) pH scale and the acidity of different types of precipitation

Q14. Explain the environmental and health effects of acid rain:

(a) Damage to buildings and monuments (Taj Mahal, Red Fort) — chemical mechanism of marble corrosion

(b) Effects on aquatic ecosystems — acidification of lakes and rivers, aluminium toxicity to fish

(c) Effects on forests — nutrient leaching, damage to leaves and roots

(d) Effects on soil — acidification, mobilisation of toxic metals

(e) Human health effects — respiratory diseases from acid aerosols

Q15. Acid rain is a growing concern in India despite being less publicised than air pollution. Discuss:

(a) Why the Indo-Gangetic Plain is becoming an acid rain hotspot (high SO₂ and NOₓ emissions, meteorology)

(b) The damage to Indian monuments and heritage sites from acid rain and other pollutants

(c) The Supreme Court's interventions to protect the Taj Mahal (Taj Trapezium Zone)

(d) Control strategies: flue gas desulphurisation, use of low-sulphur coal, catalytic converters, and international cooperation

Q17. A coal sample contains 2.5% sulphur by mass. When burned in a power plant, all sulphur is converted to SO₂.

(a) Write the balanced equation for the combustion of sulphur to SO₂.

(b) Calculate the mass of SO₂ produced from burning 1000 tonnes of this coal.

(c) If 50% of this SO₂ is converted to H₂SO₄ in the atmosphere, calculate the mass of H₂SO₄ formed and the volume of 0.01 M acid rain this could produce.

[Given: Atomic masses: S = 32, O = 16, H = 1]

Q18. The marble of the Taj Mahal contains calcium carbonate (CaCO₃). Acid rain containing H₂SO₄ reacts with it.

(a) Write the balanced chemical equation for this reaction.

(b) If 1 kg of H₂SO₄ falls on the monument, calculate the mass of CaCO₃ dissolved.

(c) If the monument loses 5 kg of CaCO₃ per year due to acid rain, calculate the annual volume of 0.1 M H₂SO₄ equivalent to this damage.

[Given: Molar masses: CaCO₃ = 100 g/mol, H₂SO₄ = 98 g/mol]

Q19. A lake in Sweden has a pH of 4.5 due to acid rain. The lake volume is 10 million litres.

(a) Calculate the H⁺ ion concentration in the lake.

(b) Calculate the total moles of H⁺ in the lake.

(c) To restore the lake to pH 6.5, calculate the mass of CaCO₃ (limestone) needed to neutralise the excess acid.

[Given: Molar mass of CaCO₃ = 100 g/mol]