Question 1

Which reagent is used to deprotonate a terminal alkyne to form a good nucleophile for subsequent reactions?

Accepted Answer

NaNH\_2

Question 2

When a terminal alkyne reacts with formaldehyde followed by acid workup, what is the major product?

Accepted Answer

Primary alcohol

Question 3

Which of the following best describes the product of hydrogenation of an alkyne using Lindlar's catalyst?

Accepted Answer

cis-Alkene

Question 4

What is the product when a terminal alkyne is treated with excess Br\_2?

Accepted Answer

Tetra-bromoalkane

Question 5

Which reaction conditions will convert an alkyne to a trans-alkene?

Accepted Answer

Na, NH\_3 (liq)

Question 6

What is the major product when 1-butyne is treated with HgSO\_4 and H\_2SO\_4?

Accepted Answer

2-butanone

Question 7

Which of the following reagents will result in anti-Markovnikov hydration of a terminal alkyne?

Accepted Answer

BH\_3, THF; H\_2O\_2, NaOH

Question 8

Which product is formed when 2-butyne is hydrogenated with excess H\_2 and Pd/C?

Accepted Answer

Butane

Question 9

What is the expected product when 1-hexyne is treated with HBr in the presence of peroxides?

Accepted Answer

1-bromohexane

Question 10

Which of the following best describes the mechanism for the formation of a secondary alcohol from a terminal alkyne and an aldehyde?

Accepted Answer

Nucleophilic addition followed by acid workup

Question 11

A student wants to synthesize trans-2-butene from 2-butyne. Which reagents should they use?

Accepted Answer

Na, NH\_3 (liq)

Question 12

Which of the following is a common misconception about the hydration of alkynes?

Accepted Answer

That hydration of alkynes always produces alcohols directly

Question 13

Which product is formed when 1-hexyne is treated with Br\_2 in CH\_2Cl\_2?

Accepted Answer

1,2-dibromohexene

Question 14

What is the role of sodium amide (NaNH\_2) in the synthesis of alkynes?

Accepted Answer

Deprotonates terminal alkynes to generate acetylide ions

Question 15

Which of the following reactions will yield a primary alcohol from a terminal alkyne?

Accepted Answer

Reaction with formaldehyde followed by acid workup

Question 16

Which product is formed when 2-butyne is treated with HBr in the absence of peroxides?

Accepted Answer

2-bromobutene

Question 17

What is the expected product when a terminal alkyne is treated with BH\_3, followed by H\_2O\_2 and NaOH?

Accepted Answer

Aldehyde

Question 18

Which of the following is true about the addition of HBr to alkynes in the presence of peroxides?

Accepted Answer

The addition follows anti-Markovnikov regioselectivity

Question 19

A chemist wants to selectively hydrogenate an alkyne to a cis-alkene. Which catalyst should be used?

Accepted Answer

Lindlar's catalyst

Question 20

Which of the following statements about alkynes is correct?

Accepted Answer

Terminal alkynes are more acidic than alkenes

Summary of Reactions of Alkynes (Ch. 9)

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