Question 1

Which of the following is the correct IUPAC name for the compound shown below?

$$\mathrm{CH_3$-CH_2$-CH(CH_3$)-CH_2$-CH_3$}$$

Accepted Answer

3-methylhexane

Question 2

Given the Newman projection below, which wedge-and-dash structure correctly represents the molecule?

$$\mathrm{CH_3$-CH_2$-CH(OH)-CH_2$-CH_3$} ($$looking down the C2–C3 bond)

Accepted Answer

OH and CH$$_3$$ are anti to each other

Question 3

Which of the following pairs are enantiomers?

Accepted Answer

Two molecules with identical connectivity but opposite configuration at all chiral centers

Question 4

Which of the following compounds is chiral?

Accepted Answer

$$\mathrm{CH_3CH(OH)CH_2CH_3}$$

Question 5

Which of the following is a constitutional isomer of cyclobutane with a methyl group?

Accepted Answer

Methylbutene

Question 6

For the chair conformation of cyclohexane, which substituent experiences the greatest 1,3-diaxial interaction?

Accepted Answer

$$\mathrm{tBu}$$

Question 7

Which of the following species is more stable?

(a) Cyclohexane with all substituents equatorial
(b) Cyclohexane with one substituent axial and one equatorial

Accepted Answer

Structure (a)

Question 8

Which combination of $$K_{eq}$$ and $$\Delta G$$ best describes a reaction that strongly favors products at equilibrium?

Accepted Answer

$$K_{eq} \u003e 1; \Delta G \u003c 0$$

Question 9

For the following transformation, predict the change in entropy ($$\Delta S$$):

$$\mathrm{C_2H_4} \xrightarrow{Br_2$} \mathrm{C_2H_4Br_2}$$

Accepted Answer

$$\Delta S \u003c 0$$

Question 10

In a two-step reaction mechanism, which step is typically the rate-determining step?

Accepted Answer

The step with the highest activation energy ($$E_a)$$

Question 11

Which of the following is the correct pattern of electron flow for the first step in an $$S_N1$$ reaction?

Accepted Answer

Loss of leaving group

Question 12

Which of the following sites is nucleophilic (N*) in the molecule $$\mathrm{C_6H_5OH}$$?

Accepted Answer

The oxygen atom of the OH group

Question 13

Which of the following rearrangements leads to a more stable carbocation?

Accepted Answer

A hydride shift from a secondary to a tertiary carbon

Question 14

Which bond has the highest bond dissociation energy according to the provided table?

Accepted Answer

$$\mathrm{C-H} in $$methane

Question 15

Which substituent causes the largest 1,3-diaxial interaction in cyclohexane?

Accepted Answer

$$\mathrm{C(CH_3$)_3}$$

Question 16

Which of the following is true about the equilibrium between two chair conformations of methylcyclohexane?

Accepted Answer

The conformation with the methyl group equatorial is favored

Question 17

Which of the following is a correct statement about entropy ($$\Delta S) in a $$reaction where two molecules combine to form one?

Accepted Answer

$$\Delta S is $$negative

Question 18

Which of the following is the correct electron flow for the second step in an $$S_N1$$ reaction?

Accepted Answer

Nucleophilic attack

Question 19

Which of the following is the most stable species in the pair below?

(a) Cyclohexane with a tert-butyl group equatorial
(b) Cyclohexane with a tert-butyl group axial

Accepted Answer

Structure (a)

Organic Chemistry: Structure, Nomenclature, Stereochemistry, and Reaction Mechanisms

Study Guide - Practice Questions