Assertion (A): Coal based thermal power stations contribute to acid rain. Reason (R): Oxides of carbon are emitted when the coal burns.

1. This is an Assertion-Reason question about coal power stations and acid rain. 2. Assertion (A): Coal based thermal power stations contribute to acid rain. This is true. Burning coal, especially coal with sulfur impurities, releases sulfur dioxide (SO2) and nitrogen oxides (NOx) into the atmosphere. These gases react with water, oxygen, and other chemicals to form sulfuric acid and nitric acid, which fall to earth as acid rain. 3. Reason (R): Oxides of carbon are emitted when the coal burns. This is true. Burning coal (a fossil fuel containing carbon) primarily produces carbon dioxide (CO2), an oxide of carbon. Carbon monoxide (CO) can also be produced. 4. Evaluating the relationship: Both A and R are true. Does R explain A? While coal burning *does* produce oxides of carbon (R), it is the emission of *sulfur dioxide* and *nitrogen oxides* that primarily causes acid rain (A). Carbon dioxide contributes to ocean acidification but is not the main cause of acid rain. Therefore, R is true but is NOT the correct explanation for A. 5. The official answer key is (A) 'Both A and R are individually true and R is the correct explanation of A'. This contradicts the scientific understanding that sulfur and nitrogen oxides, not carbon oxides, are the primary cause of acid rain from coal combustion. If we must follow the key (A), the analysis would incorrectly state that carbon oxides cause acid rain. *Assuming the key (A) is correct implies a misunderstanding of acid rain chemistry within the context of the exam.* Based on science, the answer should be (B).