Key properties and reactions of butanone (CH3COCH2CH3)

Steps:

• Recall butanone structure: unsymmetrical ketone with carbonyl between C1 (methyl) and C3 (ethyl).
• Evaluate A: dehydration applies to alcohols, not ketones; no alkene product like propene forms.
• Evaluate B: Tollens' reagent tests aldehydes via oxidation; ketones inert.
• Evaluate C: HCN adds to carbonyl via nucleophilic attack by CN-, not electrophilic.
• Evaluate D: NaBH4 reduces ketone to secondary alcohol butan-2-ol, with chiral carbon at C2.

Why D is correct:

• NaBH4 reduces ketones to secondary alcohols; butan-2-ol (CH3CH(OH)CH2CH3) has a chiral center at the carbon bearing OH, as it bonds to four different groups (H, OH, CH3, CH2CH3).

Why the others are wrong:

• A: Ketones resist dehydration; concentrated H2SO4 does not yield CH3CH=CH2 (propene) from butanone.
• B: Butanone lacks aldehydic H, so no mirror formation with Tollens' reagent.
• C: Carbonyl carbon is electrophile, but HCN reaction proceeds by nucleophilic addition of CN- to C=O.

Final answer: D