Question 1

Describe a qualitative, nonspectroscopic means for distinguishing terminal alkynes from internal ones.

Accepted Answer

Add a solution of Cu⁺ or Ag⁺. Terminal alkynes react to form insoluble metal acetylides which precipitate cipate.

Question 2

Give the IUPAC name for (CH3)2C(CH2CH3)C=CCH(CH3)2.

Accepted Answer

2,5,5-trimethylhept-3-yne

Question 3

To a solution of propyne in diethyl ether, one molar equivalent of CH3Li was added and the resulting mixture was stirred for 0.5 hour. After this time, an excess of D2O was added. Describe the major organic product(s) of this reaction.

Accepted Answer

A)  CH3C≡CD + CH4 
B)  CH3C≡CCH3 
C)  CD3C≡CD3 
D)  CH3C≡CCD3 
E)  CH3C≡CD + CH3D 
A)  CH3C≡CD + CH4 
B)  CH3C≡CCH3 
C)  CD3C≡CD3 
D)  CH3C≡CCD3 
E)  CH3C≡CD + CH3D A

Question 4

What is the correct IUPAC name for the following structure?

Accepted Answer

A)  (Z) 1-cyclopentyl-3,6-dimethylhept-3-en-1-yne 
B)  (
E)  1-cyclopentyl-3,6-dimethylhept-1-yn-3-ene 
C)  (Z) 1-cyclopentyl-4,7-dimethylhept-4-en-2-yne 
D)  (
E)  1-cyclopentyl-3,6-dimethylhept-3-en-1-yne 
A)  (Z) 1-cyclopentyl-3,6-dimethylhept-3-en-1-yne 
B)  (
E)  1-cyclopentyl-3,6-dimethylhept-1-yn-3-ene 
C)  (Z) 1-cyclopentyl-4,7-dimethylhept-4-en-2-yne 
D)  (
E)  1-cyclopentyl-3,6-dimethylhept-3-en-1-yne

Question 5

Provide the IUPAC name for the compound below.

Accepted Answer

1-chloro-4-methyl-2-

Question 6

Draw an acceptable structure for hex- 2-yne.

Accepted Answer

The answer of Draw an acceptable structure for hex- 2-yne....

Question 7

What is the major organic product that results when 1-heptyne is treated with 2 equivalents of HBr?

Accepted Answer

A)  2,3-dibromo-1-heptene 
B)  2,3-dibromo-2-heptene 
C)  1,2-dibromoheptane 
D)  2,2-dibromoheptane 
E)  1,1-dibromoheptane 
A)  2,3-dibromo-1-heptene 
B)  2,3-dibromo-2-heptene 
C)  1,2-dibromoheptane 
D)  2,2-dibromoheptane 
E)  1,1-dibromoheptane

Question 8

Provide the major organic product of the reaction below.

Accepted Answer

The answer of Provide the major organic product of the...

Question 9

Provide the major organic product of the reaction shown below.

Accepted Answer

The answer of Provide the major organic product of the...

Question 10

Name the compound shown below.

Accepted Answer

6,6-dimeth

Question 11

What is the major product of the following acid/catalyzed hydration reaction?

Accepted Answer

A) 
  
B) 
  
C) 
  
D) 
  
E) 
  
A) 
  
B) 
  
C) 
  
D) 
  
E)

Question 12

How many distinct internal alkynes exist with a molecular formula of C6H10?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 13

Complete the following reaction sequences below by filling-in the missing reagents or structures.

Accepted Answer

The answer of Complete the following reaction sequences below by...

Question 14

Treatment of hex-2-yne with mercuric sulfate in dilute sulfuric acid yields a mixture of two ketones. Similar treatment of hex-3-yne produces a single ketone instead of a mixture. Explain.

Accepted Answer

The two carbons of the triple bond in he

Question 15

The pi bond of an alkyne is ________ and ________ than the pi bond of an alkene.

Accepted Answer

A)  shorter, stronger 
B)  shorter, weaker 
C)  longer, stronger 
D)  longer, weaker 
A)  shorter, stronger 
B)  shorter, weaker 
C)  longer, stronger 
D)  longer, weaker

Question 16

Provide the structure of the major organic product(s) in the reaction below.
CH3CH2CH2CH2CH2­C꓿C­CH2CH3   $\rightarrow$

Accepted Answer

CH₃CH₂CH

Question 17

What is the pKa of a terminal alkyne?

Accepted Answer

A)  4 
B)  10 
C)  16 
D)  25 
E)  44 
A)  4 
B)  10 
C)  16 
D)  25 
E)  44

Question 18

A mixture of hept-1-yne, hept-2-yne, and hept-3-yne was hydrogenated in the presence of a platinum catalyst until hydrogen uptake ceased. If one assumes that the hydrogenation went to completion, how many $\underline{\text{ different  }}$ seven-carbon hydrocarbons were produced?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  6 
E)  8 
A)  1 
B)  2 
C)  3 
D)  6 
E)  8

Question 19

Draw and name all terminal alkynes with molecular formula C5H8.

Accepted Answer

CH₃CH₂CH₂C≡CH, 1-pentyn

Question 20

Which of the following bases will favorably deprotonate a terminal alkyne?
(More than one answer is possible.)

Accepted Answer

A)  n-BuLi 
B)  LDA 
C)  NaOMe 
D)  PhMgBr (Ph=phenyl) 
A)  n-BuLi 
B)  LDA 
C)  NaOMe 
D)  PhMgBr (Ph=phenyl)

Exam 9: Alkynes

Describe a qualitative, nonspectroscopic means for distinguishing terminal alkynes from internal ones.

Give the IUPAC name for (CH3)2C(CH2CH3)C=CCH(CH3)2.

To a solution of propyne in diethyl ether, one molar equivalent of CH3Li was added and the resulting mixture was stirred for 0.5 hour. After this time, an excess of D2O was added. Describe the major organic product(s) of this reaction.

What is the correct IUPAC name for the following structure?

Provide the IUPAC name for the compound below.

Draw an acceptable structure for hex- 2-yne.

What is the major organic product that results when 1-heptyne is treated with 2 equivalents of HBr?

Provide the major organic product of the reaction below.

Provide the major organic product of the reaction shown below.

Name the compound shown below.

What is the major product of the following acid/catalyzed hydration reaction?

How many distinct internal alkynes exist with a molecular formula of C6H10?

Complete the following reaction sequences below by filling-in the missing reagents or structures.

Treatment of hex-2-yne with mercuric sulfate in dilute sulfuric acid yields a mixture of two ketones. Similar treatment of hex-3-yne produces a single ketone instead of a mixture. Explain.

The pi bond of an alkyne is ________ and ________ than the pi bond of an alkene.

Provide the structure of the major organic product(s) in the reaction below. CH3CH2CH2CH2CH2­C꓿C­CH2CH3 →\rightarrow→

What is the pKa of a terminal alkyne?

Draw and name all terminal alkynes with molecular formula C5H8.

Which of the following bases will favorably deprotonate a terminal alkyne? (More than one answer is possible.)

Introduction and Review

Structure and Properties of Organic Molecules

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

Stereochemistry

Alkyl Halides: Nucleophilic Substitution and Elimination

Structure and Synthesis of Alkenes

Reactions of Alkenes

Structure and Synthesis of Alcohols

Reactions of Alcohols

Infrared Spectroscopy and Mass Spectrometry

Nuclear Magnetic Resonance Spectroscopy

Ethers, Epoxides, and Thioethers

Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

Aromatic Compounds

Reactions of Aromatic Compounds

Ketones and Aldehydes

Amines

Carboxylic Acids

Carboxylic Acid Derivatives

Condensations and Alpha Substitutions of Carboxyl Compounds

Carbohydrates and Nucleic Acids

Amino Acids, Peptides, and Proteins

Lipids

Synthetic Polymers

Filters

Give the IUPAC name for (CH₃)₂C(CH₂CH₃)C=CCH(CH₃)₂.

To a solution of propyne in diethyl ether, one molar equivalent of CH₃Li was added and the resulting mixture was stirred for 0.5 hour. After this time, an excess of D₂O was added. Describe the major organic product(s) of this reaction.

How many distinct internal alkynes exist with a molecular formula of C₆H₁₀?

The pi bond of an alkyne is and than the pi bond of an alkene.

Draw and name all terminal alkynes with molecular formula C₅H₈.