Question 1

How many stereoisomers are possible for the structure below (consider both chirality centers and cis/trans isomerism with respect to the C=C bond)?

Accepted Answer

Four

Question 2

Which of the following alkenes can exhibit E/Z isomerism?

Accepted Answer

3-hexene

Question 3

Which of the following alkenes is expected to have the lowest heat of hydrogenation?

Accepted Answer

trans-2-butene

Question 4

Which of the following carbocations is most likely to undergo a rearrangement?

Accepted Answer

$$\mathrm{CH_3CH^+CH_2CH_3}$$

Question 5

Which species below acts as the nucleophile in the acid-catalyzed addition of water to an alkene?

Accepted Answer

H$$_2O$$

Question 6

Which of the following energy diagrams best describes the epoxidation of cyclohexene?

Accepted Answer

C

Question 7

How many of the following alkynes would yield a single ketone product upon acid-catalyzed hydration? 1-butyne, 2-butyne, 2-pentyne, 3-hexyne, 1-hexyne.

Accepted Answer

Three

Question 8

Which of the following correctly depicts the mechanistic first step in the addition of HCl to cyclopentene?

Accepted Answer

Protonation of the alkene by HCl

Question 9

Which of the following reactions is concerted?

Accepted Answer

Epoxidation of an alkene with MCPBA

Question 10

A student treats cis-2-hexene with MCPBA. What is the expected stereochemistry of the product?

Accepted Answer

A racemic mixture of enantiomers

Question 11

Which of the following best explains why trans-2-butene has a lower heat of hydrogenation than cis-2-butene?

Accepted Answer

Trans isomer is more stable due to less steric strain

Question 12

Which of the following reagents would convert 3-hexyne to trans-3-hexene?

Accepted Answer

Na/NH$$_3$$

Question 13

Which of the following is a Markovnikov addition reaction?

Accepted Answer

Addition of HBr to propene

Question 14

Which of the following statements about carbocation rearrangements is correct?

Accepted Answer

Hydride and methyl shifts can occur to stabilize carbocations

Question 15

Which of the following best describes the product of hydroboration-oxidation of 1-hexene?

Accepted Answer

1-hexanol (anti-Markovnikov addition)

Question 16

Which of the following is true about the energy diagram for a reaction with three elementary steps, where the first step is endothermic and the second and third steps are exothermic?

Accepted Answer

The first transition state is the highest energy point

Question 17

Which of the following reagents would you use to convert an alkyne to a cis-alkene?

Accepted Answer

H$$_2/$$Lindlar's catalyst

Question 18

Which of the following is a correct statement about epoxidation of alkenes?

Accepted Answer

Epoxidation is a concerted process

Question 19

Which of the following best describes the mechanism for acid-catalyzed hydration of an alkene?

Accepted Answer

Protonation of the alkene, formation of carbocation, nucleophilic attack by water

Organic Chemistry: Alkenes, Alkynes, Stereochemistry, and Reaction Mechanisms – Study Guide

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