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Correct Answer: A
Correct Answer: A
Method / Topic: Organic Chemistry
The correct option matches the required rule and the given information.
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Correct Answer: A
Method / Topic: Organic Chemistry
The enolate has electron density at its alpha carbon and donates an electron pair to the electrophilic carbonyl carbon of another ethanal molecule. Therefore it functions as a carbon nucleophile. The attacked carbonyl oxygen becomes an alkoxide before protonation gives the beta-hydroxy aldehyde. This conclusion follows from electron flow, functional-group behavior, and the stated experimental conditions. For MCAT organic chemistry, first mark the nucleophile, electrophile, leaving group, and any resonance-stabilized intermediate; then track bonds rather than memorizing a product name. Check stereochemistry, charge, and carbon count before choosing an
, and interpret evidence without overclaiming. Always reconcile the proposed structure with every observation in the
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PASSAGE 4 — ALDOL REACTION AND PURIFICATION Two molecules of ethanal react under dilute basic conditions. An enolate forms reversibly and attacks the carbonyl carbon of another ethanal molecule, initially producing 3-hydroxybutanal. Heating promotes loss of water to form an alpha,beta-unsaturated aldehyde. The reaction mixture is separated by silica-gel chromatography, using a solvent whose polarity can be gradually increased. QUESTION 10: In the first carbon–carbon bond-forming step, the enolate acts primarily as
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Correct Answer: A
Method / Topic: Organic Chemistry
The correct option matches the required rule and the given information.
Short Explanation
Detailed Explanation
Correct Answer: A
Method / Topic: Organic Chemistry
The enolate has electron density at its alpha carbon and donates an electron pair to the electrophilic carbonyl carbon of another ethanal molecule. Therefore it functions as a carbon nucleophile. The attacked carbonyl oxygen becomes an alkoxide before protonation gives the beta-hydroxy aldehyde. This conclusion follows from electron flow, functional-group behavior, and the stated experimental conditions. For MCAT organic chemistry, first mark the nucleophile, electrophile, leaving group, and any resonance-stabilized intermediate; then track bonds rather than memorizing a product name. Check stereochemistry, charge, and carbon count before choosing an
, and interpret evidence without overclaiming. Always reconcile the proposed structure with every observation in the
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