See image — Aldehydes Ketones and Carboxylic Acids Chemistry Question

💡 Solution & Explanation

Concept: When a gem-dicarboxylic acid (malonic acid type) is heated, it undergoes decarboxylation (loss of CO2) to give a mono-carboxylic acid. Then, further heating causes loss of water. Step 1 - Identify the starting material: The structure shown is cyclohexane-1,1-dicarboxylic acid (a gem-dicarboxylic acid where both -COOH groups are on the same carbon of the cyclohexane ring). Step 2 - First heating step (Delta, -CO2): Gem-dicarboxylic acids (malonic acid derivatives) readily undergo decarboxylation upon heating to lose one CO2, yielding cyclohexane-1-carboxylic acid (cyclohexanecarboxylic acid). This is a monocarboxylic acid. Step 3 - Second heating step (Delta, -H2O): A simple monocarboxylic acid upon heating does not form an anhydride intermolecularly under normal conditions without a second carboxylic acid group nearby. However, since the product after decarboxylation is simply cyclohexanecarboxylic acid (a mono-basic acid), and the question asks for the final product after both steps, the product is the monobasic acid (cyclohexanecarboxylic acid). The second step (-H2O) here refers to the elimination within the decarboxylation mechanism or describes the overall transformation. Step 4 - Why not anhydride options (a), (b), or (c): An anhydride requires two carboxylic acid groups to condense. After decarboxylation, only one -COOH remains on the cyclohexane. A cyclic anhydride from a single -COOH is not possible. Furthermore, cis/trans anhydrides would require a dicarboxylic acid with geometric isomerism (like phthalic acid), which is not the case here. So options (a), (b), and (c) are eliminated. Step 5 - Conclusion: The product after decarboxylation (-CO2) and loss of water (-H2O, likely referring to the tautomeric/mechanistic steps) is a mono-basic acid, i.e., cyclohexanecarboxylic acid. Therefore, the correct answer is A.