Nucleophilic Addition to Carbonyl Forms Cyanohydrin

Steps:

• Identify CH3CHO as acetaldehyde, an aldehyde with a carbonyl group.
• Recognize HCN/CN- reaction as nucleophilic addition to the electrophilic carbonyl carbon.
• CN- adds to C=O, followed by H+ to oxygen, yielding CH3CH(OH)CN.
• Name the product: three-carbon chain with CN and OH on carbon 2, so 2-hydroxypropanenitrile.

Why C is correct:

• Nucleophilic addition occurs as CN- (nucleophile) attacks the carbonyl carbon (electrophile), per carbonyl addition mechanism; product formula CH3CH(OH)CN confirms 2-hydroxypropanenitrile naming.

Why the others are wrong:

• A: Incorrectly labels as electrophilic addition; carbonyls undergo nucleophilic addition.
• B: Wrong reaction type (electrophilic) and product name (2-hydroxyethanenitrile implies two carbons, but it's three).
• D: Correct reaction type but wrong product name (ethanenitrile for two carbons, not three).

Final answer: C