{"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 a ketone, while the second reaction involves the hydrolysis of a nitrile to form a carboxylic acid.", "goal": "Select the correct reagents that facilitate the transformation of butan-2-one to 2-hydroxy-2-methylbutanenitrile and the conversion of the nitrile to a carboxylic acid."}, "summary": "This problem requires selecting appropriate reagents for two organic reactions. The first reaction involves the nucleophilic addition of NaCN to butan-2-one, which is facilitated by NaHSO3 to yield 2-hydroxy-2-methylbutanenitrile. The second reaction involves the hydrolysis of the nitrile to form a carboxylic acid, which is effectively achieved using HCl. The correct reagents are A = NaHSO3 and B = HCl."}