Organic Chemistry Flashcards
7 cards from real MCAT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Organic Chemistry flashcards as text
Which of the following best explains why carboxylic acids have higher boiling points than alcohols of similar molecular weight?
Answer: Carboxylic acids form stable dimers via two hydrogen bonds
Carboxylic acids dimerize through two intermolecular hydrogen bonds between the carbonyl oxygen and O–H groups, effectively doubling the interaction energy and raising boiling points.
What is the product when an ester reacts with excess LiAlH4 followed by aqueous workup?
Answer: Two alcohols
LiAlH4 reduces esters all the way to two alcohols: one from the acyl portion and one from the alkoxide leaving group (both end up as primary alcohols).
Which of the following pairs are diastereomers?
Answer: (2R,3S)-tartaric acid and (2R,3R)-tartaric acid
Diastereomers are stereoisomers that are not mirror images; (2R,3S)-tartaric acid and (2R,3R)-tartaric acid differ at only one chiral center and are therefore diastereomers.
In an aldol condensation reaction, what type of bond is formed in the beta-hydroxy carbonyl intermediate?
Answer: C–C bond between the alpha carbon of one carbonyl and the carbonyl carbon of another
In aldol addition, the enolate (alpha carbon nucleophile) of one molecule attacks the electrophilic carbonyl carbon of another, forming a new C–C bond to give a beta-hydroxy carbonyl compound.
Which protecting group strategy would allow selective acylation of an amine in the presence of an alcohol?
Answer: Protect the alcohol as a TBS ether, then acylate the free amine
Converting the alcohol to a silyl ether (TBS) blocks the OH from reacting, leaving the amine free for selective acylation under mild conditions.
What is the correct order of decreasing reactivity toward electrophilic aromatic substitution (EAS)?
Answer: Aniline > benzene > nitrobenzene
Aniline (–NH2 is a strong activator) > benzene (no substituent) > nitrobenzene (–NO2 is a strong deactivator), reflecting electron density on the ring.
Which of the following correctly describes the Diels-Alder reaction?
Answer: A concerted [4+2] cycloaddition between a conjugated diene and a dienophile
The Diels-Alder reaction is a concerted, pericyclic [4+2] cycloaddition that proceeds through a six-membered cyclic transition state, forming a cyclohexene product stereospecifically.