Figure 6 shows how different energy resources were used in the United Kingdom (UK) to generate electricity on one day in June 2018. The UK government plans to stop using coal-fired power stations by 2025.

Explain one environmental problem caused when electricity is generated by burning coal.

Burning coal is a combustion reaction that releases large amounts of gases into the atmosphere. - **Greenhouse Gases:** The primary product is carbon dioxide (CO₂), a greenhouse gas. These gases accumulate in the atmosphere and trap infrared radiation (heat) from the sun, preventing it from escaping back into space. This leads to a gradual increase in the Earth's average temperature, known as global warming, which causes climate change. - **Acid Rain:** Coal often contains sulfur impurities. When burned, this produces sulfur dioxide (SO₂). This gas can react with water and oxygen in the atmosphere to form sulfuric acid, which falls as acid rain. Acid rain can harm forests, acidify lakes and rivers (killing fish), and corrode stone buildings.