Question 1: Acid rain is formed when sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) are released into the atmosphere and react with water vapour to produce sulphuric acid and nitric acid. These acids then fall to the ground with rain, causing environmental damage.

Answer: Acid rain forms when SO₂ and NOₓ react with water vapour in the atmosphere, creating sulphuric and nitric acids that fall with rain.

Question 1: Define 'acid rain'.

Answer: Acid rain is precipitation that contains acidic components, mainly sulphuric and nitric acids, resulting from atmospheric pollution.

Question 2: Explain the chemical process by which SO₂ causes acid rain.

Answer: Sulphur dioxide reacts with water vapour in the atmosphere to form sulphuric acid (H₂SO₄). The reaction involves SO₂ dissolving in water and undergoing oxidation to form sulphuric acid, which then precipitates as acid rain.

Question 1: Calculate the pH of a rainwater sample that contains 1.0 × 10⁻⁴ mol/dm³ of sulphuric acid (H₂SO₄). Use the formula pH = -log[H⁺].

Answer: pH = 4

Question 2: If the concentration of nitrogen oxides (NOₓ) in the atmosphere is 5.0 × 10⁻⁶ mol/dm³, how many moles are present in a 10 dm³ volume?

Answer: 50 × 10⁻⁶ mol or 5.0 × 10⁻⁵ mol

Question 1: Describe a simple method to measure the acidity of rainfall. Include the variables that need to be controlled and safety precautions.

Answer: A simple method involves collecting rainwater in a clean container and measuring its pH using pH indicator paper or a pH meter. Variables to control include the volume of sample and avoiding contamination. Safety precautions include wearing gloves and eye protection, and handling chemicals carefully.

Question 2: Identify two major sources of sulphur dioxide and nitrogen oxides in the environment. Explain how industrial processes contribute to acid rain.

Answer: Major sources include burning fossil fuels in power stations and vehicles. Industrial processes release SO₂ and NOₓ, which react in the atmosphere to form acids that cause acid rain.

Question 1: A series of rainwater samples from different locations show pH values of 4.2, 4.8, 5.0, and 3.9. Which sample indicates the most acidic rain, and what does this imply about pollution levels?

Answer: The sample with pH 3.9 is the most acidic, indicating higher pollution levels of sulphur and nitrogen oxides at that location.

Question 2: Data shows that areas near heavy traffic have higher concentrations of NOₓ and more acidic rain. Explain the relationship between traffic pollution and acid rain formation.

Answer: Traffic emissions release nitrogen oxides into the atmosphere, which react with water vapour to form nitric acid. This increases the acidity of rain, leading to more acid rain in high-traffic areas.

Question 1: Suggest two methods industries can use to reduce SO₂ and NOₓ emissions to prevent acid rain.

Answer: Industries can install scrubbers to remove SO₂ from emissions and switch to cleaner energy sources like natural gas or renewable energy to reduce NOₓ emissions.

Question 2: Discuss the environmental and economic impacts of acid rain on agriculture, forests, and buildings.

Answer: Acid rain damages crops and reduces soil fertility, harming agriculture. It causes forests to weaken and die by damaging leaves and soil chemistry. Acid rain accelerates the corrosion of buildings and monuments, leading to costly repairs. Economically, it increases costs for maintenance and environmental cleanup, while environmentally it leads to loss of biodiversity and ecosystem imbalance.