An environmental problem caused by Sulphur (IV) oxide is

Step 1: Analyze the question The question asks which environmental problem is caused by sulphur (IV) oxide (SO₂).

Step 2: Explain the concept Sulphur (IV) oxide is released when fuels containing sulphur (coal, diesel, petroleum) are burned. It also comes from gas flaring, industrial smelting, and volcanic activity. This is a major concern in places like the Niger Delta, where gas flaring is common.

In the atmosphere, SO₂ reacts with oxygen and water vapour to form sulphuric acid:

• 2SO₂ + O₂ → 2SO₃
• SO₃ + H₂O → H₂SO₄ (sulphuric acid)

This acid falls to the ground with rainfall, causing acid rain.

Step 3: Evaluate the options

• A. Acid rain: Correct. SO₂ (and nitrogen oxides) are the main causes.
• B. Deforestation: This is the clearing of forests by humans through logging and farming. It is not caused by SO₂, although acid rain can damage trees.
• C. Global warming: This is mainly caused by greenhouse gases such as carbon dioxide and methane, not SO₂.
• D. Erosion: This is caused by water, wind, and poor land management, not SO₂.

Step 4: Answer The correct answer is A. acid rain.

Effects of acid rain to remember: it damages crops and forests, corrodes buildings and zinc roofing sheets, makes soil acidic, and harms aquatic life in rivers and lakes.

Exam tip: Remember "Sulphur → Sour rain." Link SO₂ and NO₂ with acid rain, and CO₂ and CH₄ with global warming. Also, CO is linked to poisoning, and CFCs to ozone depletion.