Final answer:
We care if coal has trace amounts of sulfur because burning it releases sulfur dioxide, leading to the formation of acid rain. This has several detrimental effects on both natural and human-made environments, justifying ongoing efforts to reduce sulfur emissions from coal combustion. Therefore, the correct option in the final answer to why we care if coal has trace amounts of sulfur is: c. burning coal can lead to acid rain.
Step-by-step explanation:
We care if coal has trace amounts of sulfur because burning coal that contains sulfur releases sulfur dioxide (SO₂) into the atmosphere. When this sulfur dioxide combines with water, it forms sulfuric acid, leading to the formation of acid rain. Acid rain has a detrimental impact on the environment; it can lower the pH of lakes and waterways, causing harm to aquatic life, corrode buildings and monuments, and it also lead to soil degradation affecting plant growth. High sulfur content in coal is due to the presence of pyrite (FeS₂) which gets released as SO₂ during the combustion process. Efforts are ongoing to reduce the sulfur content in coal to mitigate these environmental issues.
Additionally, the impact of these sulfur emissions is not only environmental but also economic, as the damage caused by acid rain can be costly to manage and repair. The sulfur content in coal varies depending on its type and the conditions under which the coal was formed. For instance, bituminous coal typically has a higher sulfur content due to the presence of ancient seawater sulfur deposits. Coal from freshwater origins, like certain deposits in the western United States, often has much less sulfur.