Deck 11: Alkynes and Synthesis

Question 1

What is the product of the following reaction?

A)I
B)II
C)III
D)IV

Answer 1

I

Question 2

Which of the following about the physical properties of alkynes is not true?

A)Alkynes have low melting and boiling points.
B)Melting and boiling points increase as the number of carbons increases.
C)Alkynes are soluble in organic solvents.
D)Alkynes are soluble in water.

Answer 2

Alkynes are soluble in water.

Question 3

Which of the following explains why 1-pentyne has a slightly higher boiling point than 1-pentene?

A)1-Pentyne has more carbons than 1-pentene.
B)1-Pentyne has more carbons per hydrogen than 1-pentene.
C)1-Pentyne is linear while 1-pentene is trigonal planar.
D)The C-C triple bond in 1-pentyne is more polar than the C-C double bond in 1-pentene.

Answer 3

The C-C triple bond in 1-pentyne is more polar than the C-C double bond in 1-pentene.

Question 4

Which of the following represents an internal alkyne?

A)Only I and II
B)Only I and III
C)Only II and IV
D)Only II and III

Question 5

Give the IUPAC name for the following compound.

A)3-sec-Butyl-1,4-octadiyne
B)3-Isopropyl-1,5-octadiyne
C)3-Isopropyl-1,5-nonadiyne
D)3-sec-Butyl-1,4-nonadiyne

Question 6

Give the IUPAC name for the following compound.

A)4-Chloro-4-methyl-2-heptyne
B)3-Chloro-3-methyl-4-heptyne
C)3-Chloro-3-methyl-4-hexyne
D)4-Chloro-4-methyl-2-hexyne

Question 7

Which of the following statements about alkynes is not true?

A)Alkynes undergo many addition reactions.
B)Alkynes are more polarizable than alkenes.
C)Both p bonds of a C-C triple bond are weaker than a C-C s bond.
D)The electrons in the p bonds of alkynes are more tightly held than those of alkenes.

Question 8

What is the product of the following reaction?

A)I
B)II
C)III
D)IV

Question 9

Give the IUPAC name for the following compound.

A)4-Methyl-4-penten-1-yne
B)2-Methyl-2-hexen-5-yne
C)5-Methyl-4-hexen-1-yne
D)2-Methyl-2-penten-4-yne

Question 10

Which method would work the best in accomplishing the following transformation?

A)[1] HBr; [2] 2eq.NaNH₂
B)[1] Br₂; [2] 2eq.NaNH₂
C)[1] Br₂,H₂O; [2] NaNH₂
D)[1]BH₃,THF; [2] H₂O₂,NaOH; [3] NaNH₂

Question 11

Give the IUPAC name for the following compound.

A)6,6-Dimethyl-3-octyne
B)3,3-Dimethyl-3-octyne
C)3,3-Dimethy-5-octyne
D)6-Ethyl-6-methyl-3-heptyne

Question 12

Give the IUPAC name for the following compound.

A)4,4-Diethyl-1-octyne
B)4,4-Dipropyl-1-heptyne
C)4,4-Dipropyl-6-heptyne
D)4,4-Diethyl-6-octyne

Question 13

Give the IUPAC name for the following compound.

A)trans-2-Acetylenecyclohexanol
B)trans-2-Ethynylcyclohexanol
C)trans-2-Acetylene-1-cyclohexanol
D)trans-2-Ethylenecyclohexanol

Question 14

Which of the following represents a terminal alkyne?

A)Only I and II
B)Only II and III
C)Only I and III
D)Only II and IV

Question 15

Give the IUPAC name for the following compound.

A)2,5-Dimethyl-3-heptyne
B)3,6-Dimethy-4-heptyne
C)2,5-Dimethyl-3-octyne
D)3,6-Dimethyl-4-octyne

Question 16

How many degrees of unsaturation are introduced by a triple bond?

A)0
B)1
C)2
D)3

Question 17

Which of the following alkynes is a symmetrical alkyne?

A)I
B)II
C)III
D)IV

Question 18

What is the product of the following sequence of reactions?

A)I
B)II
C)III
D)IV

Question 19

How many s bonds and p bonds are present in a triple bond?

A)One s bond and one p bond.
B)One s bond and two p bonds.
C)Two s bonds and one p bond.
D)Two s bonds and two p bonds.

Question 20

Which of the following molecular formulas is consistent with the formula for a molecule containing one alkyne and no other degrees of unsaturation?

A)I
B)II
C)III
D)IV

Question 21

What is the major organic product of the following reaction?

A)I
B)II
C)III
D)IV

Question 22

Which of the following represents a keto-enol tautomeric pair?

A)I
B)II
C)III
D)IV

Question 23

What is the major organic product of the following reaction?

A)I
B)II
C)III
D)IV

Question 24

Which of the following anions is the most basic?

A)I
B)II
C)III
D)IV

Question 25

Which of the following bases cannot deprotonate acetylene? You are given the pK_a values of the conjugate acids in parentheses.

A)Only I and II
B)Only I and III
C)Only II and III
D)Only II and IV

Question 26

Which of the indicated hydrogen in the following compounds is the most acidic?

A)I
B)II
C)III
D)IV

Question 27

What is the reagent required to accomplish the following transformation?

A)SOCl₂
B)2eq.HCl
C)Cl₂
D)Br₂/CCl₄

Question 28

Which of the following bases can deprotonate acetylene? You are given the pK_a values of the conjugate acids in parentheses.

A)Only I and II
B)Only I and III
C)Only II and III
D)Only II and IV

Question 29

Which of the following compounds can be an enol tautomer of 1,3-cyclohexandione?

A)Only I and II
B)Only I and III
C)Only II and III
D)I,II,and III

Question 30

What is the major organic product of the following reaction?

A)I
B)II
C)III
D)IV

Question 31

In the addition of HBr to 1-butyne,the nucleophile in the first step of the mechanism is

A)the Csp-H1s bond of 1-butyne.
B)the C-C triple bond of 1-butyne.
C)the H atom in HBr.
D)the Br ion.

Question 32

Which of the following statements about the reactions of alkynes is not true?

A)Alkynes contain easily broken p bonds.
B)Alkynes undergo addition reactions.
C)When alkynes undergo two sequential addition reactions,four new s bonds are formed.
D)When alkynes undergo two sequential addition reactions,two new s bonds and a p bond are formed.

Question 33

Which of the following compounds is a tautomer of 2-hexanone?

A)Only I and II
B)Only I and III
C)Only II and III
D)I,II,and III

Question 34

What is the major product of the following reaction?

A)Only I
B)Only II
C)Only III
D)I,II,and III

Question 35

What is the relationship between the keto and enol forms of acetone,CH₃COCH₃?

A)Same compounds
B)Diastereomers
C)Enantiomers
D)Constitutional isomers

Question 36

Which of the following statements about tautomers is true?

A)Tautomers differ in the position of a single bond and a hydrogen atom.
B)Tautomers differ in the position of a double bond and a carbon atom.
C)Tautomers differ in the position of a double bond and a hydrogen atom.
D)Tautomers differ in the position of a single bond and a carbon atom.

Question 37

In the addition of HBr to 1-butyne,the electrophile in the first step of the mechanism is

A)the Csp-H1s bond of 1-butyne.
B)the C-C triple bond of 1-butyne.
C)the H atom in HBr.
D)the Br ion.

Question 38

Rank the following compounds in order of decreasing basicity,putting the most basic first.

A)I > II > III
B)III > II > I
C)III > I > II
D)II > III > I

Question 39

Which of the indicated hydrogen in the following compounds is the least acidic?

A)I
B)II
C)III
D)IV

Question 40

What is (are)the product(s)of the following reaction?

A)Only I
B)Only II
C)Only III
D)I,II,and III

Question 41

What is the major product of the following reaction sequence?

A)I
B)II
C)III
D)IV

Question 42

Give the IUPAC name for the following compound.

A)R-1-butyn-3-ol
B)S-1-butyn-3-ol
C)R-3-butyn-1-ol
D)S-3-butyn-1-ol

Question 43

What is the major organic product of the following reaction?

A)I
B)II
C)III
D)IV

Question 44

What is the major organic product of the following reaction?

A)I
B)II
C)III
D)IV

Question 45

Give the IUPAC name for the following compound.

A)R-4-bromo-1-pentyne
B)S-4-bromo-1-pentyne
C)R-3-bromo-5-pentyne
D)S-3-bromo-5-pentyne

Question 46

What is the major product of the following reaction?

A)I
B)II
C)III
D)IV

Question 47

Determine the product of the following reaction.

A)I
B)II
C)III
D)IV

Question 48

What is the starting material in the following reaction?

A)I
B)II
C)III
D)IV

Question 49

What is (are)the major organic product(s)of the following reaction?

A)Only I and II
B)Only II and III
C)Only I and III
D)I,II,and III

Question 50

What is the major product of the following reaction?

A)I
B)II
C)III
D)IV

Question 51

What is the major product of the following reaction?

A)I
B)II
C)III
D)IV