The shared property is being a secondary alcohol. 2-butanol, cyclohexanol, and 2-pentanol all have the hydroxyl group attached to a carbon that is bonded to two other carbon atoms. 1-propanol has the hydroxyl group attached to a primary carbon, making it a primary alcohol.
Question 2
Which of these compounds does not contain a ketone functional group?
propanone
acetophenone
cyclohexanone
benzaldehyde
✓
Correct Answer
benzaldehyde
The shared property is containing a ketone functional group, which is a carbonyl group (C=O) bonded to two carbon atoms. Propanone, acetophenone, and cyclohexanone are all ketones. Benzaldehyde contains an aldehyde functional group, where the carbonyl carbon is bonded to at least one hydrogen atom.
Question 3
Which of these compounds does not have a six-carbon parent chain in its IUPAC name?
cyclohexane
2-methylpentane
2,3-dimethylbutane
✓
hexane
Correct Answer
2,3-dimethylbutane
The shared property is having a six-carbon parent chain. Hexane, 2-methylpentane, and cyclohexane (as a ring) all have six carbons in their main chain or ring structure. 2,3-dimethylbutane has a four-carbon parent chain (butane) with two methyl substituents.
Question 4
Which of these molecules is not chiral?
cis-1,2-dimethylcyclopropane
1,2-dichloropropane
2-bromobutane
meso-tartaric acid
✓
Correct Answer
meso-tartaric acid
The shared property is being a chiral molecule, meaning it is non-superimposable on its mirror image and lacks an internal plane of symmetry. 2-bromobutane, 1,2-dichloropropane, and cis-1,2-dimethylcyclopropane are all chiral. Meso-tartaric acid possesses chiral centers but is achiral due to an internal plane of symmetry.
Question 5
Which of these molecules does not exhibit extended pi-conjugation?
1,4-pentadiene
✓
acrolein (propenal)
1,3-butadiene
benzene
Correct Answer
1,4-pentadiene
The shared property is exhibiting extended pi-conjugation, where pi bonds are separated by exactly one single bond, allowing for electron delocalization. 1,3-butadiene, benzene, and acrolein all have conjugated pi systems. 1,4-pentadiene has its two double bonds separated by two single bonds, making them isolated and not conjugated.
Question 6
Which of these alkyl halides is least likely to undergo an SN2 reaction with a strong nucleophile?
methyl iodide
1-chloropropane
2-bromo-2-methylpropane
✓
bromomethane
Correct Answer
2-bromo-2-methylpropane
The shared property is being a primary or methyl alkyl halide, which are typically favored for SN2 reactions due to minimal steric hindrance. Methyl iodide, 1-chloropropane, and bromomethane are all primary or methyl halides. 2-bromo-2-methylpropane is a tertiary alkyl halide, which undergoes SN2 reactions very slowly or not at all due to significant steric hindrance around the electrophilic carbon.
Question 7
Which of these is not a primary amine?
aniline
diethylamine
✓
methylamine
isopropylamine
Correct Answer
diethylamine
The shared property is being a primary amine, meaning the nitrogen atom is bonded to one carbon atom and two hydrogen atoms. Methylamine, aniline, and isopropylamine are all primary amines. Diethylamine is a secondary amine because the nitrogen atom is bonded to two carbon atoms and one hydrogen atom.
Question 8
Which of these compounds is not aromatic?
benzene
furan
cyclooctatetraene
✓
pyridine
Correct Answer
cyclooctatetraene
The shared property is being an aromatic compound, which typically means it is cyclic, planar, fully conjugated, and obeys Hückel's rule (4n+2 pi electrons). Benzene (6 pi electrons), pyridine (6 pi electrons, including lone pair in p orbital), and furan (6 pi electrons, including one lone pair in p orbital) are all aromatic. Cyclooctatetraene has 8 pi electrons and is non-planar (tub-shaped), thus it is not aromatic.
Question 9
Which of these alkenes cannot exhibit E/Z isomerism?
2-butene
2-methyl-2-butene
✓
3-hexene
1,2-dichloroethene
Correct Answer
2-methyl-2-butene
The shared property is the ability to exhibit E/Z isomerism, which requires each carbon of the double bond to be attached to two different groups. 2-butene, 1,2-dichloroethene, and 3-hexene all meet this criterion. 2-methyl-2-butene has one sp2 carbon atom bonded to two identical methyl groups, preventing E/Z isomerism.
Question 10
Which of these carbocations is least stabilized by resonance?
isopropyl carbocation
✓
triphenylmethyl carbocation
benzyl carbocation
allyl carbocation
Correct Answer
isopropyl carbocation
The shared property is having significant stabilization through resonance (delocalization of the positive charge over multiple atoms). Allyl, benzyl, and triphenylmethyl carbocations are all highly stabilized by resonance. Isopropyl carbocation is a secondary carbocation and is stabilized primarily by hyperconjugation and induction, but not by resonance.
Question 11
Three of these are good leaving groups in nucleophilic substitution. Which one is not?
hydroxide ion (OH-)
✓
bromide ion (Br-)
chloride ion (Cl-)
tosylate ion (OTs-)
Correct Answer
hydroxide ion (OH-)
The shared property is being a good leaving group, which means it is a weak base and can stabilize the negative charge after departing. Chloride ion, bromide ion, and tosylate ion are all good leaving groups. Hydroxide ion is a strong base and therefore a poor leaving group in most nucleophilic substitution reactions.
Question 12
Which of these functional groups does not contain a carbonyl group?
carboxylic acid
ester
ether
✓
amide
Correct Answer
ether
The shared property is containing a carbonyl group (C=O). Esters, amides, and carboxylic acids all contain a carbonyl group. An ether functional group consists of an oxygen atom bonded to two alkyl or aryl groups (R-O-R') and does not contain a carbonyl group.
Question 13
Which of these compounds does not contain exactly one chiral center?
2-butanol
2,3-dibromobutane
✓
1-bromo-1-chloroethane
lactic acid
Correct Answer
2,3-dibromobutane
The shared property is containing exactly one chiral center (a carbon atom bonded to four different groups). 2-butanol, lactic acid, and 1-bromo-1-chloroethane each possess a single chiral center. 2,3-dibromobutane contains two chiral centers.
Question 14
Which of these compounds does not end with the suffix '-ol' in its IUPAC name?
cyclohexanol
methanol
ethanol
propanal
✓
Correct Answer
propanal
The shared property is being an alcohol, which is indicated by the '-ol' suffix in IUPAC nomenclature. Ethanol, cyclohexanol, and methanol are all alcohols. Propanal is an aldehyde, and its IUPAC name ends with the suffix '-al'.
Question 15
Which of these reactions is least likely to proceed through a carbocation intermediate?
SN1 reaction of tert-butyl bromide
SN2 reaction of methyl iodide
✓
hydration of propene in acidic conditions
E1 reaction of 2-methyl-2-butanol
Correct Answer
SN2 reaction of methyl iodide
The shared property is proceeding through a carbocation intermediate. SN1 reactions, E1 reactions, and acid-catalyzed hydration of alkenes all involve the formation of a carbocation intermediate. An SN2 reaction of methyl iodide is a concerted, one-step mechanism that does not involve a carbocation intermediate.