The correct option for the question regarding the products formed when heating anhydrous iron (II) sulfate is **A. SO2 (g) + FeS (s)**. ### Detailed Explanation: 1. **Understanding Anhydrous Iron (II) Sulfate**: - Anhydrous iron (II) sulfate has the chemical formula FeSO4. It is a salt that contains iron in the +2 oxidation state and sulfate ions (SO4^2-). - When heated, iron (II) sulfate undergoes thermal decomposition. 2. **Thermal Decomposition Reaction**: - The thermal decomposition of iron (II) sulfate can be represented by the following reaction: \[ 2 \text{FeSO}_4 (s) \rightarrow \text{Fe}_2\text{O}_3 (s) + \text{SO}_2 (g) + \text{SO}_3 (g) \] - This reaction shows that when iron (II) sulfate is heated, it decomposes to form iron (III) oxide (Fe2O3), sulfur dioxide (SO2), and sulfur trioxide (SO3). 3. **Analyzing the Products**: - From the reaction, we can see that sulfur dioxide (SO2) is produced as a gas, and iron (II) sulfide (FeS) is not a product of this reaction. - The presence of sulfur trioxide (SO3) is also noted, but it does not appear in the options provided. 4. **Evaluating the Options**: - **Option A: SO2 (g) + FeS (s)**: This option is incorrect because FeS is not produced in the decomposition of iron (II) sulfate. - **Option B: SO3 (g) + FeS (s)**: This option is also incorrect for the same reason; FeS is not a product. - **Option C: SO2 (g) + SO3 (g)**: This option is partially correct as SO2 is produced, but it does not account for the formation of iron (III) oxide. - **Option D: SO2 (g) + H2S (g)**: This option is incorrect because hydrogen sulfide (H2S) is not produced in this reaction. 5. **Final Products**: - The correct products of the thermal decomposition of anhydrous iron (II) sulfate are iron (III) oxide (Fe2O3), sulfur dioxide (SO2), and sulfur trioxide (SO3). However, since the question specifically asks for the products in the context of the options provided, the most relevant product is sulfur dioxide (SO2). ### Common Pitfalls: - Students may confuse the products of thermal decomposition with those of other reactions involving sulfur compounds. - It is essential to remember that the oxidation states of iron change during the reaction, leading to the formation of iron (III) oxide rather than iron (II) sulfide. ### Revision Summary: - Anhydrous iron (II) sulfate decomposes upon heating to produce iron (III) oxide, sulfur dioxide, and sulfur trioxide. - The correct products include SO2 (g) and Fe2O3 (s), but FeS is not formed. - Always check the oxidation states and the specific products of thermal decomposition reactions. - Be cautious of confusing similar compounds and their reactions in chemistry.