{"knowledge_schema": {"broad_category": "Chemistry \u2192 Organic Chemistry \u2192 Reactions and Reagents", "refinement": "This problem involves identifying suitable reagents for specific organic reactions, focusing on nucleophilic addition and subsequent hydrolysis.", "specific_scope": "The first reaction involves the addition of cyanide to an aldehyde, while the second reaction involves the conversion of a nitrile to a carboxylic acid.", "goal": "Select the correct reagents that facilitate the transformation of propanal to 2-hydroxy-2-methylpropanenitrile and then convert the nitrile to the corresponding carboxylic acid."}, "summary": "In this problem, we need to identify the appropriate reagents for two organic reactions. The first reaction involves the nucleophilic addition of cyanide to propanal, leading to the formation of a hydroxynitrile, which requires a reagent that can stabilize the intermediate, such as NaHSO3. The second reaction involves hydrolyzing the nitrile to form a carboxylic acid, which is typically done using an acid like HCl. Therefore, the correct choice of reagents is C = NaHSO3 and D = HCl."}