Key properties and reactions of butanone (CH3COCH2CH3)

Steps:

• Recall butanone structure: unsymmetrical ketone with carbonyl between C1 (methyl) and C3 (ethyl).
• Evaluate A: Ketones resist dehydration; no alkene formation like CH3CH=CH2.
• Evaluate B: Test Tollens' reagent specificity for aldehydes via oxidation.
• Evaluate C: Classify HCN addition as nucleophilic attack on carbonyl carbon.
• Evaluate D: Consider NaBH4 reduction product and stereochemistry.

Why D is correct:

• NaBH4 reduces ketone to secondary alcohol CH3CH(OH)CH2CH3 (butan-2-ol), with chiral center at C2 due to four different substituents, yielding racemic chiral product.

Why the others are wrong:

• A: Dehydration applies to alcohols, not ketones; butanone cannot form CH3CH=CH2.
• B: Tollens' reagent detects aldehydes; ketones lack aldehydic hydrogen for silver mirror.
• C: HCN adds via nucleophilic mechanism (CN- attacks carbonyl), not electrophilic.

Final answer: D