Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) W hat is the IUPAC name for the follow ing alkyne?
1)
A) 5-Bromo-2-heptyne
B) 5-Bromo-5,5-dimethylhexyne
C) 5-Bromo-5-methyl-2-hexyne
D) 3-Bromo-5-heptyne
E) 2-Bromo-2-methyl-4-hexyne
Answ er: C
2) How many distinct terminal alkynes exist w ith a molecular for mula of C 5 H8 ?
A) 1
B) 2
C) 3
D) 4
2)
E) 5
Answ er: B
3) How many distinct internal alkynes exist w ith a molecular for mula of C 6 H10 ?
A) 1
B) 2
C) 3
D) 4
3)
E) 5
Answ er: C
4) W hat is the common name for the follow ing alkyne?
4)
A) neohexyne
B) trimethylpropyne
C) trimethylacetylene
D) isopropylacetylene
E) tert-butylacetylene
Answ er: E
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
5) W rite structures and give IUPAC names for all alkynes w ith molecular for mula C5 H8 .
Answ er:
1
5)
6) Give the IUPAC name for (CH3 )2 C(CH2 CH3 )CCCH(CH3 )2 .
6)
Answ er: 2, 5, 5-trimethyl-3-heptyne
7) Give the IUPAC name for HCCCH2 CH2 CH3 .
7)
Answ er: 1-pentyne
8) Give the IUPAC name for BrCH2 CH2 CCCH2 CH3 .
8)
Answ er: 1-bromo-3-hexyne
9)
9) Draw an acceptable structure for acetylene.
Answ er: H
C
C
H
10) Draw an acceptable structure for 3-sec-butyl-1-heptyne.
10)
Answ er:
11)
11) Draw an acceptable structure for 2-hexyne.
Answ er:
12) Provide the systematic name of the compound show n.
12)
Answ er: 5,6,6-trimethyl-1-heptyne
13) Give the systematic name for the alkyne Cl 3 CCH2 CH2 CCCH3 .
13)
Answ er: 6,6,6-trichloro-2-hexyne
14) Provide the structure of all distinct terminal alkynes w ith a molecular for mula of
C6 H10 .
Answ er:
2
14)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
15) Give the IUPAC name for the follow ing compound.
15)
A) 2-methyl-1,3-butadiene
B) isobutadiene
C) 3-methyl-1,3-butadiene
D) isoprene
E) 2-methyl-2,3-butadiene
Answ er: A
16) W hat is the IUPAC name for the follow ing compound?
16)
A) 2Z,4Z-2, 4-heptadiene
B) trans, trans-2, 4-heptadiene
C) 2E,4E-2, 4-heptadiene
D) cis, cis-2, 4-heptadiene
E) cis, trans-2, 4-heptadiene
Answ er: E
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
17) Give the systematic name of the compound show n below .
17)
Answ er: 1, 7-dimethyl-1, 3-cycloheptadiene
18) Give the systematic name of the compound show n below .
Answ er: (S)-5-methyl-5-hexen-2-ol
3
18)
19) Name the follow ing compound:
19)
Answ er: (2E,4Z)-2, 4-hexadiene or trans, cis-2, 4-hexadiene or (2Z,2E)-2, 4-hexadiene or
cis, trans-2, 4-hexadiene
20) Provide the structure of (2E,4E)-2-chloro-2, 4-octadiene.
20)
Answ er:
21) Provide the systematic name of the compound show n.
21)
Answ er: (E)-5-methyl-5-hepten-1-yne
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
22) W hich of the follow ing improperly describes the physical properties of an alkyne?
22)
A) relatively nonpolar
B) insoluble in most organic solvents
C) less dense than w ater
D) nearly insoluble in w ater
Answ er: B
23) W hat is the hybridization of the carbon atoms numbered 1 and 2 respectively in the follow ing
structure?
A) sp2 , sp
B) sp3 , sp2
C) sp2 , sp2
Answ er: A
4
D) sp, sp
E) sp, sp2
23)
24) W hich of the follow ing statements is not true about propyne, HC
C
CH3 ?
24)
A) It contains six sigma bonds.
B) The C
C
C bond angle is 180°.
C) The H
C
H bond angle is about 109.5°.
D) It contains three pi bonds.
E) The pi bond is w eaker than the sigma bond.
Answ er: D
25) The carbon-carbon triple bond of an alkyne is composed of __________.
A) three
bonds
B) one
C) three
bonds
D) tw o
25)
bond and tw o
bonds
bonds and one
bond
Answ er: B
26) W hat are the hybridizations of the carbon atoms numbered 1 and 2 in the structure below ?
1
H3 C-CH
CH-C
26)
2
C-H
A) sp2 , sp2
B) sp3 , sp2
D) sp2 , sp
C) sp, sp
Answ er: C
27) W hat tw o atomic or bitals or hybrid atomic or bitals overlap to form the carbon -carbon
bond
27)
in ethyne?
A) sp3
sp3
B) s
s
C) sp
sp
D) sp2
sp2
E) p
p
Answ er: C
28) W hich of the follow ing statements cor rectly describes the general reactivity of alkynes?
28)
A) Alkynes are generally mor e reactive than alkenes.
B) Alkynes reacts as electrophiles, w hereas alkenes reacts as nucleophiles.
C) The
bonds of alkynes ar e higher in energy than the
bonds and are thus mor e reactive.
D) Unlike alkenes, alkynes fail to undergo electrophilic addition reactions.
E) An alkyne is an electron-rich molecule and therefor e reacts as a nucleophile.
Answ er: E
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
29) Although you might expect 1-propyne to b e mor e reactive than 1-propene in
electrophilic addition reactions, the reverse is true. Explain this using your know ledge
of the mechanism of electrophilic additions to b oth alkynes and alkenes.
Answ er: W hen HCl is added to an alkene, a secondary carbocation intermediate is
formed, CH3CHCH3. W hen HCl is added to an alkyne, a vinylic cation is for med
as an intermediate, CH3 C
CH2 . Alkynes are less stable than alkenes but vinylic
carbocations are less stable than secondary carbocations. Thus, alkenes are mor e
reactive than alkynes since the difference in stabilities betw een the carbocations
is greater than the difference in stabilities betw een the alkene and alkyne.
5
29)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
30) W hat is the maj or product of the follow ing reaction?
30)
HCl
CH3 C
CH
excess
A) CH3 CH
CH
Cl
B)
C)
D)
E)
Answ er: D
31) W hich of the follow ing is the best synthesis of 2, 2-dibromopropane
Br 2
A) CH3 CH
CH2
light
2 HBr
B) CH3 C
CH
CH3 CH
peroxide
CH2
C)
Br 2
H2 O
D) CH3 C
CH
CH3 CH
E)
2 HBr
CH2
Br 2
CCl4
Answ er: D
6
31)
32) In the addition of hydrogen bromide to alkynes in the absence of peroxides, w hich of the
32)
follow ing species is believed to b e an intermediate?
A) bromonium ion
B) vinyl anion
C) vinyl cation
D) car bene
E) vinyl radical
Answ er: C
33) __________ is produced w hen 1 equivalent of HBr is added to 1-hexyne in the presence of
33)
peroxides.
A) E-1-bromo-1-hexene
B) E-2-bromo-2-hexene
C) 2-bromo-1-hexene
D) a mixture of E and Z isomers of 1-bromo-1-hexene
E) Z-1-bromo-1-hexene
Answ er: D
34) W hich of the follow ing compounds is the maj or product w hen 1 -hexyne is treated w ith excess
HBr?
A) 1,2-dibromohexene
B) 1,1-dibromohexane
C) 2,2-dibromohexane
D) 1,2-dibromohexane
E) 1,1-dibromohexene
Answ er: C
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
35) Provide the structure of the maj or or ganic product(s) in the reaction below .
Answ er:
7
35)
34)
36) Provide the structure of the maj or or ganic product of the follow ing reaction.
36)
Answ er:
37) Provide the structure of the maj or or ganic product of the follow ing reaction.
37)
Answ er:
38) Provide the maj or or ganic product in the reaction below .
Answ er:
8
38)
39) Provide the maj or or ganic product in the reaction below .
39)
Answ er:
40) Provide the maj or or ganic product in the reaction below .
40)
Answ er:
41) Provide the maj or or ganic product in the reaction below .
41)
Answ er:
42) Provide the maj or or ganic product in the reaction below .
Answ er:
9
42)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
43) W hich of the follow ing are enol for ms of 2-butanone,
A)
B)
C)
D)
E)
Answ er: E
10
43)
44) W hich of the follow ing is the final and maj or product of this reaction?
A) I
B) II
C) III
D) IV
44)
E) V
Answ er: A
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
45) Provide the structure of the maj or or ganic product(s) in the reaction below .
45)
Answ er:
46) For the reaction below indicate w hether the equilibrium constant w ill be greater than 1
46)
or less than 1.
CH3 CH2 CHO
CH3 CH
CHOH
Answ er: < 1
47) Provide the structure of the intermediate w hich for ms in the first step of the reaction of
1-butyne w ith w ater in the presence of H2 SO4 /HgSO4 .
Answ er:
11
47)
48) Provide the structure of the maj or or ganic product of the follow ing reaction.
48)
Answ er:
49) Provide the maj or or ganic product in the reaction below .
Answ er:
12
49)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
50) W hich of the follow ing is the final and maj or product of this reaction?
A) I
B) II
C) III
D) IV
50)
E) V
Answ er: C
51) W hich of the alkyne addition reactions below involves an enol intermediate?
51)
A) hydr oboration/oxidation
B) treatment w ith HgSO4 in dilute H2 SO4
C) hydr ogenation
D) both A and B
E) both A and C
Answ er: D
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
52) Provide the structure of the maj or or ganic product(s) in the reaction below .
Answ er:
13
52)
53) Complete the follow ing reaction.
53)
Answ er: ethynylcyclobutane
54) Provide the structure of the maj or or ganic product of the follow ing reaction.
54)
Answ er:
55) Provide the maj or or ganic product in the reaction below .
55)
Answ er:
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
56) The reagent needed to convert 2-butyne to cis-2-butene is:
56)
A) Li/NH3
B) H+ /Zinc dust
C) Na/NH3
D) H2 /Lindlar 's catalyst
E) H2 /Pt
Answ er: D
57) The reagent needed to convert 2-butyne to trans-2-butene is:
A) H2 /Pt
B) H2 /Lindlar 's catalyst
C) Li/NH3
D) Na/NH3
E) C or D
Answ er: E
14
57)
58) A mixture of 1-heptyne, 2-heptyne, and 3-heptyne w as hydrogenated in the presence of a
58)
platinum catalyst until hydrogen uptake ceased. If one assumes that the hydrogenation w ent to
completion, how many distinct seven-carbon hydrocarbons w ere produced?
A) 1
B) 8
C) 3
D) 6
E) 2
Answ er: A
59) In the reduction of alkynes using sodium in liquid ammonia, w hich of the species below is not
believed to b e an intermediate in the commonly accepted mechanism?
A) vinyl anion
B) vinyl cation
C) vinyl radical
D) radical anion
Answ er: B
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
60) Provide the maj or or ganic product in the reaction below .
60)
Answ er:
61) An optically active compound (A), C6 H10 , reacts w ith H2 /Ni to produce compound (B),
61)
C6 H14 . (B) is optically inactive. Deduce the structures of (A) and (B).
Answ er:
62) Provide the structure of the maj or or ganic product(s) in the reaction below .
Answ er:
15
62)
59)
63) Provide the structure of the maj or or ganic product(s) in the reaction below .
CH3 CH2
C
C
CH3
63)
Na, NH3
Answ er:
64) Complete the follow ing reaction.
3-hexyne
64)
Na, NH3
Answ er: trans-3-heptene
65) Provide the structure of the maj or or ganic product of the follow ing reaction.
65)
Answ er:
66) Provide the structure of the maj or or ganic product of the follow ing reaction.
Answ er:
16
66)
67) Provide the structure of the maj or or ganic product of the follow ing reaction.
67)
Answ er:
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
68) W hich is the cor rect or der of decreasing acidity in the follow ing compounds?
H2 O
CH3 CH3
A
NH3
B
C
CH2
CH2
HC
D
68)
CH
E
A) E > A > C > B > D
B) A > C > E > D > B
C) E > D > B > A > C
D) A > E > D > B > C
E) A > E > C > D > B
Answ er: E
69) W hat are the products of the follow ing reaction,
CH3 OH + CH3 C
A) CH3 OC
C- Na +
69)
?
CH + NaCH3
B) CH3 C
CH + CH3 O- Na +
C) CH3 C
COCH3 + NaOH
D) CH3 C
CCH3 + NaOH
E) no reaction
Answ er: B
70) W hich of the species below is less basic than acetylide?
70)
A) CH3 Li
B) CH3 ONa
C) NaOH
D) both B and C
E) all of the above
Answ er: D
71) Among the compounds w ater, 1-butyne, 2-butyne, and ethane, w hich are stronger acids than
ammonia?
A) w ater and 1-butyne
B) 1-butyne and 2-butyne
C) 1-butyne and ethane
D) w ater and ethane
Answ er: A
17
71)
72) W hat type of organic product results w hen 1-butyne is treated w ith 6M aqueous NaOH?
72)
A) an alcohol
B) a sodium acetylide
C) an aldehyde
D) an enol
E) Not much reaction; most of the alkyne remains unchanged.
Answ er: E
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
73) Explain w hy HC
N is a stronger acid than HC
CH.
73)
Answ er: Because nitrogen is mor e electronegative than carbon.
74) W hich hydrogens are mor e acidic, those of benzene or those of cyclohexane? W hy?
74)
Answ er: Benzene. The carbon hybridization of benzene is sp 2 w hile that of cyclohexane is
sp3 . The mor e s character in benzene causes its hydrogens to b e mor e acidic than
those of cyclohexane.
75) W hy ar e terminal alkynes more acidic than other hydrocar bons?
75)
Answ er: The car banion w hich results upon deprotonation of a terminal alkyne has the
lone pair of electrons in an sp hybrid or bital. The greater % s character of this
orbital gives the orbital a significantly low er energy.
76) For the reaction below indicate w hether the equilibrium constant w ill be greater than 1
76)
or less than 1.
CH3 Li + CH3 C
CH
CH4 + CH3 C
CLi
Answ er: >1
77) Provide the structure of the maj or or ganic product of the follow ing reaction.
Answ er:
18
77)
78) For the reaction below indicate w hether the equilibrium constant w ill be greater than 1
78)
or less than 1.
KOH + CH3 C
CH
H2 O + CH3 C
CK
Answ er: <1
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
79) W hat is/are the maj or or ganic product(s) of the follow ing reaction,
A) HC
CBr
B) CH3 C
CCH3
C) CH3 CH2 C
D) HC
79)
CH
CCH2 CH2 Br
E) CH2
CH2 + HC
CH
Answ er: C
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
80) Provide the structure of the maj or or ganic product(s) in the reaction below .
CH3 CH2
CH
80)
1. NaNH2
2. PhCH2 Br
Answ er: CH3 CH2 C
CCH2 Ph
81) Provide the structure of the maj or or ganic product of the follow ing reaction.
Answ er:
19
81)
82) Suggest a plausible scheme for the follow ing synthesis
82)
Answ er:
83) Describe a sequence of r eactions by w hich 3-heptyne can be straightforw ar dly
83)
prepared from acetylene.
Answ er: 1)
NaNH2
2)
CH3 CH2 Br
3)
NaNH2
4)
CH3 CH2 CH2 Br
84) Describe a sequence of r eactions by w hich meso-2, 3-dibromobutane can be
84)
straightforw ardly prepared from propyne.
Answ er: 1)
NaNH2
2)
CH3 Br
3)
Na, NH3
4)
Br 2 , CCl4
85) Describe a sequence of r eactions by w hich butylbenzene can be straightforw ardly
85)
prepared from phenylacetylene.
Answ er: 1)
NaNH2
2)
CH3 CH2 Br
3)
H2 , Pt
86) Describe a sequence of r eactions by w hich CH3 CH2 CH2 COCH2 CH3 can be
straightforw ardly prepared from 1-butyne.
Answ er: 1)
NaNH2
2)
CH3 CH2 Br
3)
HgSO4 , H2 O, H2 SO4
20
86)
87) Describe a sequence of r eactions by w hich trans-2-pentene can be straightforw ardly
87)
prepared from propyne.
Answ er: 1)
NaNH2
2)
CH3 CH2 Br
3)
Na, NH3
88) Describe a sequence of r eactions by w hich the aldehyde CH3 CH2 CH2 CH2 CHO could be
88)
prepared from acetylene.
Answ er: 1)
NaNH2
2)
CH3 CH2 CH2 Br
3)
disiamylborane
4)
H2 O2 , - OH
89) Describe a sequence of r eactions by w hich cis-2-pentene could be prepared from
acetylene.
Answ er: 1)
NaNH2
2)
CH3 CH2 Br
3)
NaNH2
4)
CH3 Br
5)
H2 , Lindlar 's catalyst
21
89)
90) Complete the follow ing tree of r eactions by giving the maj or products.
Answ er:
22
90)