In organic chemistry, an alkyne is an unsaturated hydrocarbon which has at least one carbon—carbon triple bond between two carbon atoms.[1] The simplest acyclic alkynes with only one triple bond and no other functional groups form a homologous series with the general chemical formula CnH2n-2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature. Like other hydrocarbons, alkynes are generally hydrophobic but tend to be more reactive

1. Chapter 9 Alkynes

2. • 1. What is the IUPAC name of the following
compound?
•
•
•
•
A.
B.
C.
D.
5-propyl-3-heptyne
5-isopropyl-3-heptyne
5-ethyl-3-octyne
4-ethyl-5-octyne

3. • 2. Which of the following describes the orbital
overlap of the C(1) - C(2) sigma bond of 1butyne, shown below?
•
•
•
•
A.
B.
C.
D.
sp-sp
sp2-sp2
sp3-sp3
2p-2p

4. • 3. Which of the following gives only one
organic product on ozonolysis?
•
•
•
•
A.
B.
C.
D.
2-hexene
3-hexene
2-heptene
3-heptene

5. 4.
What is the IUPAC name of the following
compound?
•
•
•
•
A.
B.
C.
D.
2-methyl-5-propyl-3-heptyne
1-isopropyl-3-propyl-1-pentyne
5-ethyl-2-methyl-3-octyne
4-ethyl-7-methyl-5-octyne

6. • 5. Which one of the following describes the
C(2)-C(3) sigma bond in the structure below?
•
•
•
•
A.
B.
C.
D.
sp-sp
sp2-sp2
sp3-sp3
2p-2p

7. • 6. Select the best base to quantitatively
remove a proton from acetylene.
•
•
•
•
A.
B.
C.
D.
NaNH2
NH3
NaOH
NaOCH2CH3

8. 7.
Arrange the following in order of decreasing
base strength (strongest base first).
•
•
•
•
A.
B.
C.
D.
IV > III > II > I
II > III > I > IV
I > II > IV > III
II > III > IV > I

9. 8.
Predict the major product(s) in the reactions
below.
•
•
•
•
•
A.
B.
C.
D.
1-nonyne
2-nonyne
cis-2-nonene
trans-2-nonene

10. • 10. Which sequence of reactions works best in
synthesizing cis-3-nonene?
•
•
•
•
A.
B.
C.
D.
A
B
C
D

11. • 11. Which sequence of reactions below works
best in carrying out the following conversion?
•
•
•
•
A.
B.
C.
D.
(1) HBr
(1) Br2
(1) Br2, H2O
(1) H2O, H2SO4(cat.)
(2) excess NaNH2
(2) excess NaNH2
(2) excess NaNH2
(2) excess NaNH2

12. • 12. Which of the following is the enol intermediate in the acid-catalyzed
addition of water to propyne?
•
•
•
•
A.
B.
C.
D.
A
B
C
D

13. 13. Which reagent below would be used to
convert 2-pentyne to trans-2-pentene?
•
•
•
•
A.
B.
C.
D.
NaNH2, NH3
Na, NH3
H2, Lindlar Pd
H2O, HgSO4/H2SO4

14. 14. Select the best method to carry out the
following conversion.
•
•
•
•
A.
B.
C.
D.
A
B
C
D

15. 15. Which of the following is the correct IUPAC
name of the product for the reaction shown below?
•
•
•
•
A.
B.
C.
D.
cis-2-methyl-5-heptene
trans-2-methyl-5-heptene
cis-6-methyl-2-heptene
trans-6-methyl-2-heptene

16. • 16. Identify compound Y.
• A. 2-bromobutane
• B. meso-2,3-dibromobutane
• C. racemic (2R,3R) and (2S,3S)-2,3dibromobutane
• D. 2,3-dibromo-2-butene

17. • 17. When a terminal alkyne is treated with
sodium amide, NaNH2, in liquid ammonia,
sodium amide acts as a
•
•
•
•
•
A.
B.
C.
D.
Brønsted acid.
Brønsted base.
reducing agent.
catalyst.

18. 18. When alkynes are treated with sodium
metal, Na, in liquid ammonia, sodium acts as a
•
•
•
•
A.
B.
C.
D.
Brønsted acid.
Brønsted base.
reducing agent.
catalyst.

19. • 19. Select the best reaction sequence to make
the following ketone.
•
•
•
•
A.
B.
C.
D.
A
B
C
D