Organic Chemistry Quiz
Questions: 16 · 10 minutes
1. Which species is aromatic according to the usual criteria of cyclic conjugation, planarity, and Hückel's rule?
The cyclopropenyl anion, with four π electrons
Cyclobutadiene, with four π electrons
Planar cyclooctatetraene, with eight π electrons
The cyclopentadienyl anion, with six π electrons
2. Ethanal generally undergoes nucleophilic addition faster than propanone. What best explains this difference?
Ethanal has no polarized carbonyl bond
Propanone cannot form a tetrahedral intermediate
Ethanal is aromatic, whereas propanone is not
Ethanal has less steric hindrance and fewer electron-donating alkyl groups
3. An infrared spectrum is being used to distinguish an alcohol from an ether. Which observation most strongly supports the alcohol?
A carbon–hydrogen stretching absorption below 3000 cm⁻¹
A strong carbonyl absorption around 1700 cm⁻¹
A broad oxygen–hydrogen stretching absorption around 3200-3600 cm⁻¹
A sharp carbon–carbon triple-bond absorption around 2200 cm⁻¹
4. Ignoring splitting and integrations, how many distinct proton environments are expected in the ¹H NMR spectrum of bromoethane, CH₃CH₂Br?
Two
Three
One
Five
5. Which compound is the strongest acid under typical conditions?
Ethanol
Ethyne
Acetic acid
Ammonia
6. What is the expected organic product when 2-propanol is oxidized under conditions that convert secondary alcohols without breaking carbon–carbon bonds?
Propanoic acid
Propanone
Propene
Propanal
7. Complete acid-catalyzed hydrolysis of ethyl ethanoate produces which pair of organic compounds?
Ethanal and methanol
Ethene and ethanoic acid
Ethanol and ethanal
Ethanol and ethanoic acid
8. What best describes each carbon atom in ethene, C₂H₄?
sp² hybridized with trigonal planar geometry
sp³ hybridized with tetrahedral geometry
sp hybridized with linear geometry
sp³ hybridized with trigonal pyramidal geometry
9. Cyclohexene is treated with bromine in an inert solvent. What is the principal type of product?
An alcohol formed by hydration of the double bond
A vicinal dibromide formed by addition across the double bond
An alkane formed by reduction of the double bond
An allylic alcohol formed by substitution
10. A strong nucleophile reacts with an alkyl bromide in a polar aprotic solvent. Which substrate would generally undergo an SN2 reaction fastest?
2-Bromobutane
2-Bromo-2-methylpropane
1-Bromobutane
Bromobenzene
11. Why is an amide nitrogen generally less basic than an amine nitrogen?
The nitrogen lone pair is delocalized into the adjacent carbonyl system
The carbonyl group makes the nitrogen permanently positively charged
Amides cannot interact with acids
The amide nitrogen has no valence electrons
12. Why are the two carbon–oxygen bonds in the acetate ion equivalent?
Resonance delocalizes the negative charge across both oxygen atoms
The ion rapidly rotates around one fixed carbon–oxygen double bond
Both oxygen atoms form independent carbon–oxygen triple bonds
Hydrogen bonding continuously exchanges the two oxygen atoms
13. Propene reacts with HBr in the absence of peroxides. What is the major constitutional product?
1-Bromopropane
2-Bromopropane
1,2-Dibromopropane
Propan-2-ol
14. For a concerted E2 elimination, how should the leaving group and the hydrogen being removed ideally be oriented?
Parallel and pointing in the same direction
Perpendicular to each other
Anti-periplanar
On nonadjacent carbon atoms
15. Which functional group is characteristic of ethanol?
A carbonyl group
An amino group
A carboxyl group
A hydroxyl group
16. Pure (R)-2-butanol and pure (S)-2-butanol have what stereochemical relationship?
They are constitutional isomers
They are non-superimposable mirror images
They are diastereomers
They are identical compounds in different conformations