Question 1

Which reagent would you use to selectively reduce an alkyne to a cis-alkene?

Accepted Answer

H\_2, Lindlar's catalyst

Question 2

A terminal alkyne reacts with NaNH\_2 followed by an alkyl halide. What is the major product of this sequence?

Accepted Answer

An internal alkyne with the new alkyl group attached to the terminal carbon

Question 3

Which of the following best describes the hybridization of the carbon atoms in ethyne ($$C_2H_2$$)?

Accepted Answer

sp

Question 4

Ozonolysis of 3-methyl-2-pentene produces which set of products?

Accepted Answer

$$CH_3COCH_2CH_3$$ and $$CO_2$$

Question 5

Which of the following is the correct order of stability for the carbocations shown below?
I: tert-butyl carbocation
II: isopropyl carbocation
III: ethyl carbocation

Accepted Answer

I \u003e II \u003e III

Question 6

In an E2 elimination reaction, which of the following statements is TRUE regarding the stereochemistry of the product?

Accepted Answer

The leaving group and the hydrogen must be anti-periplanar

Question 7

Which base would you use to favor the Hofmann product over the Zaitsev product in an E2 elimination?

Accepted Answer

Potassium tert-butoxide ($$KOtBu)$$

Question 8

Which of the following ketones could NOT be prepared by acid-catalyzed hydration of an alkyne?

Accepted Answer

A ketone with no adjacent hydrogens to the carbonyl group

Question 9

What is the major organic product when 1-hexyne is treated with excess HCl?

Accepted Answer

1,1-dichlorohexane

Question 10

Which of the following mechanisms correctly represents the SN2 reaction between cyclohexyl chloride and sodium cyanide?

Accepted Answer

The nucleophile attacks from the opposite side of the leaving group, resulting in inversion of configuration

Question 11

Which of the following statements about the reactivity of alkyl halides in SN1 reactions is correct?

Accepted Answer

Tertiary alkyl halides react faster than secondary or primary alkyl halides

Question 12

Which of the following is the correct order of reactivity for the compounds below in an SN1 reaction?
I: 1-bromopropane
II: cyclohexyl bromide
III: cyclohexyl chloride
IV: benzyl chloride

Accepted Answer

IV \u003e II \u003e I \u003e III

Question 13

Which of the following reagents would convert a terminal alkyne to a methyl ketone?

Accepted Answer

HgSO\_4, H\_2SO\_4, H\_2O

Question 14

Which of the following is the expected product when 1-butyne is treated with 9-BBN followed by $$H_2O_2$$, $$NaOH$$?

Accepted Answer

Butanal ($$CH_3CH_2CH_2CHO)$$

Question 15

Which of the following statements about the product of catalytic hydrogenation of an alkyne using $$H_2$$ and Pt is correct?

Accepted Answer

The alkyne is fully reduced to an alkane

Question 16

Which of the following is the major product when 2-bromopentane is treated with sodium methoxide ($$NaOCH_3) in $$methanol?

Accepted Answer

Trans-2-pentene

Question 17

Which of the following best explains why only one product is formed in the E2 elimination of trans-1-bromo-4-methylcyclohexane with methoxide?

Accepted Answer

The anti-periplanar arrangement of the leaving group and hydrogen is only possible for one set of atoms in the chair conformation

Question 18

Which of the following is the correct product for the reaction of 1-bromocyclohexane with methanol?

Accepted Answer

Cyclohexanol

Question 19

Which of the following is the correct product for the reaction of 1-bromopropane with sodium ethoxide ($$NaOEt$$)?

Accepted Answer

Propene

Organic Chemistry Reaction Mechanisms, Stereochemistry, and Alkene/Alkyne Chemistry: Study Guide

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