Test Bank for Essential Organic Chemistry 2nd Edition By Paula Yurkanis Bruice

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Essential Organic Chemistry, 2e (Bruice)

 

Chapter 1

 

 

Electronic Structure and Covalent Bonding

 

1)

 

Atoms with the same number of protons but different numbers of neutrons are called __________.

 

Answer:

 

isotopes

 

Section:

 

 

1.1

 

2)

 

What isotope of chlorine has the same number of neutrons as Argon-38?

 

1. A)

 

17Cl

 

1. B)

 

35Cl

 

1. C)

 

36Cl

 

1. D)

 

37Cl

 

1. E)

 

38Cl

 

Answer:

 

D

 

Section:

 

 

1.1

 

3)

 

Which statement is incorrect about the atomic number of an atom?

 

1. A)

 

It equals the number of protons in its nucleus.

 

1. B)

 

It equals the number of electrons outside the nucleus.

 

1. C)

 

It equals the sum of its protons and neutrons..

 

1. D)

 

It is a whole number.

 

1. E)

 

It is given on the Periodic Table.

 

Answer:

 

C

 

Section:

 

 

1.1

 

4)

 

Which of the following elements does this electronic configuration represent?

1s2 2s2 2p5

 

 

1. A)

 

F

 

1. B)

 

C

 

1. C)

 

N

 

1. D)

 

Al

 

1. E)

 

O

 

Answer:

 

A

 

Section:

 

 

1.2

 

5)

 

Which of the following is the electronic configuration of the element Fe?

 

1. A)

 

1s2 2s2 2p6 3s2 3p6 4s2 3d6

 

1. B)

 

1s2 2s2 2p6 3s2 3p8 3d6

 

1. C)

 

1s2 2s2 2p8 3s2 3p6 4s2 3d6

 

1. D)

 

1s2 2s2 2p6 3s2 3p6 4s2 4d6

 

1. E)

 

1s2 2s2 2p6 3s2 3p6 4s2 4p6

 

Answer:

 

A

 

Section:

 

 

1.2

 

6)

 

Ar, K+, Cl- are isoelectronic elements (elements with the same number of electrons). What orbital does the last electron occupy?

 

Answer:

 

3p orbital

 

Section:

 

 

1.2

 

7)

 

The atomic number of boron is 5. The correct electronic configuration of boron is __________.

 

1. A)

 

1s2 2s3

 

1. B)

 

1s2 2p3

 

1. C)

 

1s2 2s2 2p1

 

1. D)

 

2s2 2p3

 

1. E)

 

1s2 2s2 3s1

 

Answer:

 

C

 

Section:

 

 

1.2

 

8)

 

Which of the following statements correctly describes the third electron shell that surrounds the nucleus of an atom?

 

1. A)

 

The third shell contains only s and p atomic orbitals.

 

1. B)

 

The maximum number of electrons that can occupy the third shell is 18.

 

1. C)

 

The total number of atomic orbitals present in the third shell is 16.

 

1. D)

 

The third shell can contain f orbitals.

 

1. E)

 

none of the above

 

Answer:

 

B

 

Section:

 

 

1.2

 

9)

 

Which of the following describes a hydride ion?

 

1. A)

 

a negatively charged hydrogen ion containing a pair of electrons

 

1. B)

 

a positively charged hydrogen ion

 

1. C)

 

a hydrogen ion containing a single electron

 

1. D)

 

a negatively charged OH ion

 

1. E)

 

a proton containing an extra electron

 

Answer:

 

A

 

Section:

 

 

1.3

 

10)

 

Rank the following atoms in increasing electronegativity.

 

1. A)

 

N, Na, Si, O, C

 

1. B)

 

C, N, O, Na,  Si

 

1. C)

 

O, N, C, Si, Na

 

1. D)

 

Si, C, N, O, Na

 

1. E)

 

Na, Si, C, N, O

 

Answer:

 

E

 

Section:

 

 

1.3

 

11)

 

Using the symbol δ+ and δ-, indicate the direction of the polarity in the indicated bond.

 

 

 

Answer:

 

 

 

 

Section:

 

 

1.3

 

12)

 

Covalent bonds may be polar or nonpolar. What property of the atoms forming a given bond accounts for this fact?

 

Answer:

 

electronegativity

 

Section:

 

 

1.3

 

13)

 

The compound methylamine, H3C-NH2, contains a C-N bond. In this bond, which of the following best describes the charge on the nitrogen atom?

 

1. A)

 

+1

 

1. B)

 

slightly positive

 

1. C)

 

uncharged

 

1. D)

 

slightly negative

 

1. E)

 

-1

 

Answer:

 

D

 

Section:

 

 

1.3

 

14)

 

Which of the compounds below bond predominantly via ionic bonding?

 

1. A)

 

KCl

 

1. B)

 

CF4

 

1. C)

 

NH3

 

1. D)

 

both A and B

 

1. E)

 

both B and C

 

Answer:

 

A

 

Section:

 

 

1.3

 

15)

 

What type of bonding is most important in CH3CH2CH2CH2CH2CH3?

 

1. A)

 

ionic

 

1. B)

 

hydrogen

 

1. C)

 

covalent

 

1. D)

 

polar

 

Answer:

 

C

 

Section:

 

 

1.3

 

16)

 

Which of the following contains polar covalent bonds?

 

1. A)

 

NH3

 

1. B)

 

Na2O

 

1. C)

 

H2

 

1. D)

 

KF

 

1. E)

 

both A and C

 

Answer:

 

A

 

Section:

 

 

1.3

 

17)

 

What is the name given for a species that contains a positively charged carbon atom?

 

1. A)

 

carbanion

 

1. B)

 

carbocation

 

1. C)

 

methyl radical

 

1. D)

 

carbon radical

 

1. E)

 

free radical

 

Answer:

 

B

 

Section:

 

 

1.4

 

18)

 

Which of the following is the most likely (i.e., most stable) electronic structure for C2H2?

 

1. A)

 

 

 

 

1. B)

 

 

 

 

1. C)

 

 

 

 

1. D)

 

HCCH

 

 

1. E)

 

 

 

 

Answer:

 

D

 

Section:

 

 

1.4

 

19)

 

Which of the following structures, including formal charges, is correct for diazomethane, H2CN2?

 

1. A)

 

: H2CNN:

 

 

1. B)

 

 

 

 

1. C)

 

 

 

 

1. D)

 

 

 

 

1. E)

 

 

 

 

Answer:

 

D

 

Section:

 

 

1.4

 

20)

 

What are the formal charges on nitrogen and the starred oxygen atom in the following molecule?

 

 

 

1. A)

 

N = -1, O = 0

 

1. B)

 

N = +1, O = -1

 

1. C)

 

N = +1, O = +1

 

1. D)

 

N = -1, O = -1

 

1. E)

 

N= +1, O = 0

 

Answer:

 

E

 

Section:

 

 

1.4

 

21)

 

Draw the Kekulé structure for each of the following:

1. CH3CH2OH b.    CH3CHO            c.     (CH3)3C+

 

Answer:

 

 

 

 

Section:

 

 

1.4

 

22)

 

What is the formal charge on the phosphorus in the PO43- polyatomic ion?

 

1. A)

 

-3

 

1. B)

 

-2

 

1. C)

 

-1

 

1. D)

 

0

 

1. E)

 

+1

 

Answer:

 

E

 

Section:

 

 

1.4

 

23)

 

The formal charge on nitrogen in the compound below is __________.

 

 

 

1. A)

 

+2

 

1. B)

 

+1

 

1. C)

 

0

 

1. D)

 

-1

 

1. E)

 

-2

 

Answer:

 

B

 

Section:

 

 

1.4

 

24)

 

The Kekulé structure of pentane is shown below. Draw the condensed structural formula which corresponds to this Lewis structure.

 

 

 

Answer:

 

CH3(CH2)3CH3

 

Section:

 

 

1.4

 

25)

 

Draw condensed structures for the four compounds with formula C3H9N.

 

Answer:

 

CH3CH2CH2NH2

CH3CH2NHCH3

(CH3)2CHNH2

(CH3)3N

 

Section:

 

 

1.4

 

26)

 

Write a Lewis structure for the molecule given below.

 

CH2O

 

Answer:

 

 

 

 

Section:

 

 

1.4

 

27)

 

Expand the condensed structure below to show the covalent bonds and the lone-pair electrons.

 

(CH3)2CHCH2CHO

 

Answer:

 

 

 

 

Section:

 

 

1.4

 

28)

 

Draw the shape of a 2p orbital.

 

Answer:

 

 

 

 

Section:

 

 

1.5

 

29)

 

What is the name given to a three-dimensional region where an electron is found?

 

1. A)

 

nucleus

 

1. B)

 

ion

 

1. C)

 

sphere

 

1. D)

 

orbital

 

1. E)

 

cloud

 

Answer:

 

D

 

Section:

 

 

1.5

 

30)

 

How many distinct p orbitals exist in the second electron shell?

 

1. A)

 

0

 

1. B)

 

1

 

1. C)

 

2

 

1. D)

 

3

 

1. E)

 

4

 

Answer:

 

D

 

Section:

 

 

1.5

 

31)

 

Which describes the bond strength or bond dissociation energy?

 

1. A)

 

energy required to break a bond

 

1. B)

 

energy released when a bond breaks

 

1. C)

 

energy released when a bond is formed

 

1. D)

 

A and B

 

1. E)

 

A and C

 

Answer:

 

E

 

Section:

 

 

1.6

 

32)

 

Which statement is correct?

 

1. A)

 

Energy is released when a bond breaks.

 

1. B)

 

A sigma bond results from attraction of protons and electrons.

 

1. C)

 

Energy is released when a bond forms.

 

1. D)

 

Protons and electrons are repulsive.

 

1. E)

 

A carbanion is positively charged.

 

Answer:

 

C

 

Section:

 

 

1.6

 

33)

 

Both sigma (σ) and pi (π) bonds can be formed by overlapping p orbitals. Describe the difference.

 

Answer:

 

Sigma bonds are formed from the overlap of atomic orbitals along a circular axis of symmetrical nature, i.e., head-on overlap. All single bonds are sigma bonds.

 

Pi bonds are formed from the overlap of atomic orbitals along a non-symmetrical (parallel) axis, i.e., side-to-side overlap. Double and triple bonds are pi bonds.

 

Section:

 

 

1.6 and 1.8

 

34)

 

Choose the correct hybridization for the atom indicated in the molecule below.

 

CH3CH2CH2CH3

↑

 

1. A)

 

sp

 

1. B)

 

sp2

 

1. C)

 

sp3

 

1. D)

 

none of the above

 

Answer:

 

C

 

Section:

 

 

1.7

 

35)

 

What orbitals are used to form the covalent bonds in butane (CH3CH2CH2CH3)?

 

Answer:

 

The carbon-carbon σ bonds are formed by the overlap of two carbon sp3 hybrid atomic orbitals. The carbon-hydrogen σ bonds are formed by the overlap of a carbon sp3 hybrid atomic orbital and a hydrogen s orbital.

 

Section:

 

 

1.7

 

36)

 

Which of the following is a nonpolar molecule?

 

1. A)

 

HCl

 

1. B)

 

CH3Cl

 

1. C)

 

H2

 

1. D)

 

CO

 

1. E)

 

NH3

 

Answer:

 

C

 

Section:

 

 

1.3 and 1.7

 

37)

 

Which of the following is a correct formula for a compound?

 

1. A)

 

CH3CH2(CH3)2CH2CH3

 

1. B)

 

CH2CH2(CH3)CH2CH3

 

1. C)

 

CH3CH(CH3)CH2CH3

 

1. D)

 

CH3CH2(CH3)2

 

1. E)

 

C

 

Answer:

 

C

 

Section:

 

 

1.7

 

38)

 

Which of the following results from the combining of atomic orbitals?

 

1. A)

 

s orbital

 

1. B)

 

nonpolar molecule

 

1. C)

 

hybrid orbitals

 

1. D)

 

polar molecule

 

1. E)

 

sigma bond

 

Answer:

 

C

 

Section:

 

 

1.7

 

39)

 

How many electrons are involved in a carbon-carbon double bond?

 

1. A)

 

1

 

1. B)

 

2

 

1. C)

 

3

 

1. D)

 

4

 

1. E)

 

5

 

Answer:

 

D

 

Section:

 

 

1.8

 

40)

 

Which of the following describes a triple bond?

 

1. A)

 

two sigma bonds and two pi bonds

 

1. B)

 

three pi bonds

 

1. C)

 

one sigma bond and one pi bond

 

1. D)

 

two sigma bonds and one pi bond

 

1. E)

 

one sigma bond and two pi bonds

 

Answer:

 

E

 

Section:

 

 

1.9

 

41)

 

Which carbon(s) in the following molecule is (are) sp hybridized?

 

 

 

1. A)

 

carbon 1

 

1. B)

 

carbon 2

 

1. C)

 

carbon 1, 3

 

1. D)

 

carbon 4

 

1. E)

 

carbon 4, 5

 

Answer:

 

E

 

Section:

 

 

1.9

 

42)

 

Which of the following is an sp2 hybridized carbon?

 

1. A)

 

 

 

1. B)

 

∙ CH3

 

1. C)

 

 

 

1. D)

 

A and B

 

1. E)

 

A, B and C

 

Answer:

 

A

 

Section:

 

 

1.10

 

43)

 

What orbitals overlap to create the H-C bond in CH3+?

 

1. A)

 

sp3-sp3

 

1. B)

 

sp2-sp3

 

1. C)

 

s–p

 

1. D)

 

s–sp2

 

1. E)

 

s–sp3

 

Answer:

 

D

 

Section:

 

 

1.10

 

44)

 

The lone-pair electrons of the methyl anion occupy a __________ orbital.

 

1. A)

 

s

 

1. B)

 

p

 

1. C)

 

sp

 

1. D)

 

sp2

 

1. E)

 

sp3

 

Answer:

 

E

 

Section:

 

 

1.10

 

45)

 

Explain why the water molecule has a bent shape and a bond angle less than 109.5°.

 

Answer:

 

The electron replusion between the two lone pairs of electrons on the oxygen of water causes the O-H bonds to squeeze close together.

 

Section:

 

 

1.11

 

46)

 

Which of the following is closest to the C-O-C bond angle in CH3-O-CH3?

 

1. A)

 

180°

 

1. B)

 

120°

 

1. C)

 

109.5°

 

1. D)

 

90°

 

1. E)

 

160°

 

Answer:

 

C

 

Section:

 

 

1.11

 

47)

 

Triethylamine [(CH3CH2)3N] is a molecule in which the nitrogen atom is __________ hybridized and the CNC bond angle is __________.

 

1. A)

 

sp2; >109.5°

 

1. B)

 

sp2; <109.5°

 

1. C)

 

sp3; >109.5°

 

1. D)

 

sp3; <109.5°

 

1. E)

 

sp; 109.5°

 

Answer:

 

D

 

Section:

 

 

1.12

 

48)

 

The N-H bond in the ammonium ion, NH4+, is formed by the overlap of what two orbitals?

 

1. A)

 

sp3-sp3

 

1. B)

 

sp3-sp2

 

1. C)

 

sp2-sp2

 

1. D)

 

sp2-s

 

1. E)

 

sp3-s

 

Answer:

 

E

 

Section:

 

 

1.12

 

49)

 

Among the hydrogen halides, the strongest bond is found in __________ and the longest bond is found in __________.

 

1. A)

 

HF; HF

 

1. B)

 

HF; HI

 

1. C)

 

HI; HF

 

1. D)

 

HI; HI

 

1. E)

 

HCl; HBr

 

Answer:

 

B

 

Section:

 

 

1.13

 

50)

 

Which bond in the following molecule is the shortest?

 

 

 

1. A)

 

bond 1

 

1. B)

 

bond 2

 

1. C)

 

bond 3

 

1. D)

 

bond 4

 

1. E)

 

bond 5

 

Answer:

 

E

 

Section:

 

 

1.14

 

51)

 

Which of the following species have tetrahedral bond angles?

 

 

 

1. A)

 

A, D and E

 

1. B)

 

A, D, E and F

 

1. C)

 

A and E

 

1. D)

 

D only

 

1. E)

 

A, B and E

 

Answer:

 

B

 

Section:

 

 

1.14

 

52)

 

The carbon-carbon double bond in ethene is __________ and __________ than the carbon-carbon triple bond in ethyne.

 

1. A)

 

stronger; shorter

 

1. B)

 

stronger; longer

 

1. C)

 

weaker; shorter

 

1. D)

 

weaker; longer

 

1. E)

 

stronger; more polar

 

Answer:

 

D

 

Section:

 

 

1.14

 

53)

 

Draw the structure of a molecule which contains only carbon and hydrogen atoms (only three of which are carbon) and in which two of the carbons are sp2 hybridized and the other is sp hybridized.

 

Answer:

 

H2CCCH2

 

Section:

 

 

1.14

 

54)

 

What is the CNN bond angle in the compound shown below?

 

 

 

1. A)

 

~60°

 

1. B)

 

~90°

 

1. C)

 

~110°

 

1. D)

 

~120°

 

1. E)

 

~180°

 

Answer:

 

D

 

Section:

 

 

1.14

 

55)

 

Why is the CH bond in ethene (H2CCH2) shorter and stronger than the CH bond in ethane(H3C-CH3)?

 

Answer:

 

The length and strength of a CH bond depends on the hybridization of the carbon atom. The more s character in the hybrid orbital used by carbon to form the bond, the shorter and stronger the bond. This is because an s orbital is closer to the nucleus than is a p  orbital. Ethene uses carbon sp2 hybridized orbitals (1/3 s character) to make its carbon-hydrogen bonds while ethane uses carbon sp3 (1/4 s character) orbitals.

 

Section:

 

 

1.14

 

56)

 

What is the predicted shape, bond angle, and hybridization for +CH3?

 

1. A)

 

trigonal planar, 120°, sp2

 

1. B)

 

trigonal planar, 120°, sp3

 

1. C)

 

trigonal planar, 109.5°, sp2

 

1. D)

 

trigonal pyramidal, 120°, sp2

 

1. E)

 

trigonal pyramidal, 109.5°, sp2

 

Answer:

 

A

 

Section:

 

 

1.8, 1.10, and 1.14

 

Essential Organic Chemistry, 2e (Bruice)

 

Chapter 5

 

 

Reactions of Alkenes and Alkynes: An Introduction to Multistep Synthesis

 

1)

 

What is the role of the p  bond of an alkene in an electrophilic addition reaction?

 

Answer:

 

The relatively loosely held p electrons of the carbon-carbon double bond attack an electrophile to begin the reaction.

 

Section:

 

 

5.0

 

2)

 

Complete the following reaction and provide a detailed, step-by-step mechanism for the process.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.1

 

3)

 

What is the product in the following reactions?

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.1 and 5.3

 

4)

 

Which of the following is the most stable carbocation?

 

 

 

1. A)

 

I

 

1. B)

 

II

 

1. C)

 

III

 

1. D)

 

IV

 

1. E)

 

V

 

Answer:

 

D

 

Section:

 

 

5.2

 

5)

 

Which of the following alkenes reacts with HCl at the slowest rate?

 

1. A)

 

 

 

 

1. B)

 

 

 

 

1. C)

 

 

 

 

1. D)

 

 

 

 

1. E)

 

 

 

 

Answer:

 

A

 

Section:

 

 

5.2

 

6)

 

Which of the following compounds will react most rapidly with HCl?

 

1. A)

 

5-methyl-1-hexene

 

1. B)

 

4-methyl-1-hexene

 

1. C)

 

(E)-5-methyl-2-hexene

 

1. D)

 

(E)-2-methyl-3-hexene

 

1. E)

 

2-methyl-2-hexene

 

Answer:

 

E

 

Section:

 

 

5.2

 

7)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.3

 

8)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.3

 

9)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.3

 

10)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.3

 

11)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.3

 

12)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.3

 

13)

 

What is the major product in the following reaction?

 

 

 

1. A)

 

I

 

1. B)

 

II

 

1. C)

 

III

 

1. D)

 

IV

 

1. E)

 

V

 

Answer:

 

C

 

Section:

 

 

5.4

 

14)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.4

 

15)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.4

 

16)

 

Complete the following reaction and provide a detailed, step-by-step mechanism for the process.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.4

 

17)

 

What is the major product from the acid-catalyzed hydration of 2-methyl-2-pentene?

 

1. A)

 

2-methylpentane

 

1. B)

 

2-methyl-1-pentanol

 

1. C)

 

2-methyl-2-pentanol

 

1. D)

 

2-methyl-3-pentanol

 

1. E)

 

1-methoxypentane

 

Answer:

 

C

 

Section:

 

 

5.4

 

18)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.4

 

19)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.5

 

20)

 

What is/are the product(s) in the following reaction?

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.5

 

21)

 

How many electrons are involved in a carbon-carbon triple bond?

 

1. A)

 

1

 

1. B)

 

2

 

1. C)

 

3

 

1. D)

 

4

 

1. E)

 

6

 

Answer:

 

E

 

Section:

 

 

5.6

 

22)

 

What is the general formula for a noncyclic alkyne?

 

1. A)

 

CnH2n+2

 

1. B)

 

CnH2n

 

1. C)

 

CnH2n-1

 

1. D)

 

CnH2n-2

 

1. E)

 

CnH2n-4

 

Answer:

 

D

 

Section:

 

 

5.6

 

23)

 

What is the IUPAC name for the following alkyne?

 

 

 

1. A)

 

5-Bromo-2-heptyne

 

1. B)

 

3-Bromo-5-heptyne

 

1. C)

 

2-Bromomethyl-4-hexyne

 

1. D)

 

5-Bromo-5,5-dimethylhexyne

 

1. E)

 

5-Bromo-5-methyl-2-hexyne

 

Answer:

 

E

 

Section:

 

 

5.7

 

24)

 

Write structures and give IUPAC names for all alkynes with the molecular formula of C5H8.

 

Answer:

 

 

 

 

Section:

 

 

5.7

 

25)

 

What is the IUPAC name for the structure shown below?

 

 

 

Answer:

 

2,5,5-trimethyl-3-heptyne

 

Section:

 

 

5.7

 

26)

 

What is the IUPAC name for the structure shown below?

 

 

 

Answer:

 

1-pentyne

 

Section:

 

 

5.7

 

27)

 

What is the IUPAC name for the structure shown below?

 

 

 

Answer:

 

1-bromo-3-hexyne

 

Section:

 

 

5.7

 

28)

 

Draw an acceptable structure for acetylene.

 

Answer:

 

HCCH

 

Section:

 

 

5.7

 

29)

 

Draw an acceptable structure for 3-sec-butyl-1-heptyne.

 

Answer:

 

 

 

 

Section:

 

 

5.7

 

30)

 

Draw an acceptable structure for 2-hexyne.

 

Answer:

 

 

 

 

Section:

 

 

5.7

 

31)

 

How many distinct terminal alkynes exist with a molecular formula of C5H8?

 

1. A)

 

1

 

1. B)

 

2

 

1. C)

 

3

 

1. D)

 

4

 

1. E)

 

5

 

Answer:

 

B

 

Section:

 

 

5.7

 

32)

 

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

 

1. A)

 

1

 

1. B)

 

2

 

1. C)

 

3

 

1. D)

 

4

 

1. E)

 

5

 

Answer:

 

C

 

Section:

 

 

5.7

 

33)

 

What is the common name for the following alkyne?

 

 

 

1. A)

 

Neohexyne

 

1. B)

 

Trimethylpropyne

 

1. C)

 

Trimethylacetylene

 

1. D)

 

tert-Butylacetylene

 

1. E)

 

Isopropylacetylene

 

Answer:

 

D

 

Section:

 

 

5.7

 

34)

 

Give the systematic name for the alkyne shown below.

 

 

 

Answer:

 

6,6,6-trichloro-2-hexyne

 

Section:

 

 

5.7

 

35)

 

Which of the following is a correct statement about the carbon-carbon triple bond in an alkyne?

 

1. A)

 

composed of one sigma bond and one pi bond

 

1. B)

 

composed of two sigma bonds and one pi bond

 

1. C)

 

composed of one sigma bond and two pi bonds

 

1. D)

 

composed of two sigma bond and two pi bond

 

1. E)

 

composed of one sigma bond, one pi bond and one delta bond

 

Answer:

 

C

 

Section:

 

 

5.8

 

36)

 

What is the hybridization of the carbon atoms numbered 1 and 2 respectively in the following structure?

 

 

 

1. A)

 

sp3, sp2

 

1. B)

 

sp2, sp2

 

1. C)

 

sp, sp

 

1. D)

 

sp2, sp

 

1. E)

 

sp, sp2

 

Answer:

 

D

 

Section:

 

 

5.8

 

37)

 

How many atoms are attached to an atoms having a sp hybridization?

 

1. A)

 

0

 

1. B)

 

1

 

1. C)

 

2

 

1. D)

 

3

 

1. E)

 

4

 

Answer:

 

C

 

Section:

 

 

5.8

 

38)

 

Which of the following statements is not true about propyne, HCCCH3?

 

1. A)

 

It contains six sigma bonds.

 

1. B)

 

It contains three pi bonds.

 

1. C)

 

The HCH bond angle is about 109.5°.

 

1. D)

 

The CCC bond angle is 180°.

 

1. E)

 

The pi bond is weaker than the sigma bond.

 

Answer:

 

B

 

Section:

 

 

5.8

 

39)

 

What two atomic orbitals or hybrid atomic orbitals overlap to form the carbon-carbon σ bond in ethyne?

 

1. A)

 

sp3sp3

 

1. B)

 

pp

 

1. C)

 

sp2sp2

 

1. D)

 

ss

 

1. E)

 

spsp

 

Answer:

 

E

 

Section:

 

 

5.8

 

40)

 

What are the hybridizations of the carbon atoms numbered 1 and 2 in the structure below?

 

1    2

H3C-CHCH-CC-H

 

1. A)

 

sp3, sp2

 

1. B)

 

sp2, sp2

 

1. C)

 

sp2, sp

 

1. D)

 

sp, sp

 

Answer:

 

D

 

Section:

 

 

5.8

 

41)

 

What is the hybridization of the carbon atom numbered 1 in the structure below?

 

 

 

1. A)

 

sp

 

1. B)

 

sp2

 

1. C)

 

sp3

 

1. D)

 

d2sp3

 

1. E)

 

sp-sp2

 

Answer:

 

A

 

Section:

 

 

5.8

 

42)

 

Which of the following improperly describes the physical properties of an alkyne?

 

1. A)

 

relatively nonpolar

 

1. B)

 

nearly insoluble in water

 

1. C)

 

less dense than water

 

1. D)

 

insoluble in most organic solvents

 

Answer:

 

D

 

Section:

 

 

5.9

 

43)

 

Which of the following are correct statements concerning unsaturated hydrocarbons?

 

1. A)

 

All unsaturated hydrocarbons are insoluble in water.

 

1. B)

 

All unsaturated hydrocarbons are soluble in nonpolar solvents.

 

1. C)

 

All unsaturated hydrocarbons are more dense than water.

 

1. D)

 

A and B

 

1. E)

 

A, B, and C

 

Answer:

 

D

 

Section:

 

 

5.9

 

44)

 

Although you might expect 1-propyne to be more reactive than 1-propene in electrophilic addition reactions, the reverse is true. Explain this using your knowledge of the mechanism of electrophilic additions to both alkynes and alkenes.

 

Answer:

 

When HCl is added to an alkene, a secondary carbocation intermediate is formed,  When HCl is added to an alkyne, a vinylic carbocation is formed as an intermediate,  Alkynes are less stable than alkenes but vinylic carbocations are less stable than secondary carbocations. Thus, alkenes are more reactive than alkynes since the difference in stabilities between the carbocations is greater than the difference in stabilities between the alkene and alkyne.

 

Section:

 

 

5.10

 

45)

 

Which of the following statements correctly describes the general reactivity of alkynes?

 

1. A)

 

An alkyne is an electron-rich molecule and therefore reacts as a nucleophile.

 

1. B)

 

The σ bonds of alkynes are higher in energy than the π bonds and are thus more

reactive.

 

1. C)

 

Unlike alkenes, alkynes fail to undergo electrophilic addition reactions.

 

1. D)

 

Alkynes are generally more reactive than alkenes.

 

1. E)

 

none of the above

 

Answer:

 

A

 

Section:

 

 

5.10

 

46)

 

Describe the role of the alkyne in the reaction between an alkyne and a hydrogen halide.

 

Answer:

 

An alkyne is an electron-rich molecule because of its two p bonds and thus an alkyne is a nucleophile. p electrons from the alkyne triple bond attack the electrophilic hydrogen of the hydrogen halide during the first step of the reaction between an alkyne and a hydrogen halide.

 

Section:

 

 

5.10

 

47)

 

What is the major product of the following reaction?

 

HCl

CH3CCH

 

 

1. A)

 

 

 

 

1. B)

 

 

 

 

1. C)

 

CH3CHCHCl

 

1. D)

 

 

 

 

1. E)

 

 

 

 

Answer:

 

B

 

Section:

 

 

5.10

 

48)

 

Provide the structure of the major organic product(s) in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.10

 

49)

 

In the addition of hydrogen bromide to alkynes, which of the following species is believed to be an intermediate?

 

1. A)

 

vinyl anion

 

1. B)

 

vinyl cation

 

1. C)

 

vinyl radical

 

1. D)

 

carbene

 

1. E)

 

none of the above

 

Answer:

 

B

 

Section:

 

 

5.10

 

50)

 

Which of the following compounds is the major product when 1-hexyne is treated with excess HBr?

 

1. A)

 

1,1-dibromohexane

 

1. B)

 

1,1-dibromohexene

 

1. C)

 

1,2-dibromohexene

 

1. D)

 

1,2-dibromohexane

 

1. E)

 

2,2-dibromohexane

 

Answer:

 

E

 

Section:

 

 

5.10

 

51)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.10

 

52)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.10

 

53)

 

Which of the following are enol forms of 2-butanone?

 

 

 

1. A)

 

 

 

 

1. B)

 

 

 

 

1. C)

 

 

 

 

1. D)

 

 

 

 

1. E)

 

 

 

 

Answer:

 

E

 

Section:

 

 

5.11

 

54)

 

What is the term used for isomers that are in rapid equilibrium?

 

1. A)

 

functonality

 

1. B)

 

keto-enol tautomers

 

1. C)

 

constitutional isomers

 

1. D)

 

conformational isomers

 

1. E)

 

cis-trans isomers

 

Answer:

 

B

 

Section:

 

 

5.11

 

55)

 

Which of the following is the final and major product of this reaction?

 

 

 

1. A)

 

I

 

1. B)

 

II

 

1. C)

 

III

 

1. D)

 

IV

 

1. E)

 

V

 

Answer:

 

A

 

Section:

 

 

5.11

 

56)

 

Provide the structure of the major organic product(s) in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.11

 

57)

 

Which of the alkyne addition reactions below involves an enol intermediate?

 

1. A)

 

hydroboration/oxidation

 

1. B)

 

treatment with HgSO4 in dilute H2SO4

 

1. C)

 

hydrogenation

 

1. D)

 

both A and B

 

1. E)

 

none of the above

 

Answer:

 

D

 

Section:

 

 

5.11

 

58)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.11

 

59)

 

Which of the following reagents gives the reaction shown below?

 

CH3CH=CH2     +     ?     →     CH3CH2CH3

 

1. A)

 

H2/HCl

 

1. B)

 

H2/H2SO4

 

1. C)

 

H2/Ni

 

1. D)

 

H2O/Ni

 

1. E)

 

H2O/H2SO4

 

Answer:

 

C

 

Section:

 

 

5.12

 

60)

 

Upon hydrogenation, which of the following alkenes releases the least heat per mole?

 

1. A)

 

3,4-dimethyl-1-hexene

 

1. B)

 

(Z)-3,4-dimethyl-2-hexene

 

1. C)

 

(E)-3,4-dimethyl-2-hexene

 

1. D)

 

(Z)-3,4-dimethyl-3-hexene

 

1. E)

 

(E)-3,4-dimethyl-3-hexene

 

Answer:

 

E

 

Section:

 

 

5.12

 

61)

 

The reagent needed to convert 2-butyne to cis-2-butene is:

 

1. A)

 

H2/Pt

 

1. B)

 

H2/Lindlar’s catalyst

 

1. C)

 

Li/NH3

 

1. D)

 

Na/NH3

 

1. E)

 

H+/Zinc dust

 

Answer:

 

B

 

Section:

 

 

5.12

 

62)

 

A mixture of 1-heptyne, 2-heptyne, and 3-heptyne was hydrogenated in the presence of a platinum catalyst until hydrogen uptake ceased. If one assumes that the hydrogenation went to completion, how many distinct seven-carbon hydrocarbons were produced?

 

1. A)

 

1

 

1. B)

 

2

 

1. C)

 

3

 

1. D)

 

6

 

1. E)

 

8

 

Answer:

 

A

 

Section:

 

 

5.12

 

63)

 

Provide the structure of the major organic product(s) in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.12

 

64)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.12

 

65)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.12

 

66)

 

What is the product when 3-heptyne reacts with the Lindlar catalyst?

 

1. A)

 

2-methyl-2-heptene

 

1. B)

 

trans-3-heptene

 

1. C)

 

cis-2-methyl-3-hexene

 

1. D)

 

cis-3-hexene

 

1. E)

 

none of the above

 

Answer:

 

D

 

Section:

 

 

5.12

 

67)

 

Which is the correct order of decreasing acidity in the following compounds?

 

H2O          CH3CH3             NH3         CH2CH2          HCCH

A                   B                         C                     D                          E

 

1. A)

 

A > E > C > D > B

 

1. B)

 

A > E > D > B > C

 

1. C)

 

E > A > C > B > D

 

1. D)

 

A > C > E > D > B

 

1. E)

 

E > D > B > A > C

 

Answer:

 

A

 

Section:

 

 

5.13

 

68)

 

Explain why HCN is a stronger acid than HCCH.

 

Answer:

 

Because nitrogen is more electronegative than carbon.

 

Section:

 

 

5.13

 

69)

 

Which hydrogens are more acidic, those of benzene or those of cyclohexane? Why?

 

 

 

Answer:

 

Benzene. The carbon hybridization of benzene is sp2 while that of cyclohexane is sp3. The more s character in benzene causes its hydrogens to be more acidic than those of cyclohexane.

 

Section:

 

 

5.13

 

70)

 

Why are terminal alkynes more acidic than other hydrocarbons?

 

Answer:

 

The carbanion which results upon deprotonation of a terminal alkyne has the lone pair of electrons in an sp hybridized orbital. The greater % s character of this orbital gives the orbital a significantly lower energy.

 

Section:

 

 

5.13

 

71)

 

Which of the species below is less basic than acetylide,  ?

 

1. A)

 

CH3Li

 

1. B)

 

CH3ONa

 

1. C)

 

NaOH

 

1. D)

 

both B and C

 

1. E)

 

all of the above

 

Answer:

 

D

 

Section:

 

 

5.13

 

72)

 

Among the compounds water, 1-butyne, 2-butyne, and ethane, which are stronger acids than ammonia?

 

1. A)

 

1-butyne and ethane

 

1. B)

 

water and 1-butyne

 

1. C)

 

water and ethane

 

1. D)

 

1-butyne and 2-butyne

 

Answer:

 

B

 

Section:

 

 

5.13

 

73)

 

What type of organic product results when 1-butyne is treated with 6M aqueous NaOH?

 

1. A)

 

a sodium acetylide

 

1. B)

 

an enol

 

1. C)

 

an alcohol

 

1. D)

 

an aldehyde

 

1. E)

 

Not much reaction; most of the alkyne remains unchanged.

 

Answer:

 

E

 

Section:

 

 

5.13

 

74)

 

Provide the structure of the major organic product of the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.13

 

75)

 

Provide the structure of the major organic product(s) in the reaction below.

 

CH3CH2CH

 

Answer:

 

CH3CH2CCCH2Ph

 

Section:

 

 

5.14

 

76)

 

Provide the structure of the major organic product of the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.14

 

77)

 

Suggest a plausible scheme for the following synthesis:

 

 

 

Answer:

 

 

 

 

Section:

 

 

5.15

 

78)

 

Describe a sequence of reactions by which 3-heptyne can be straightforwardly prepared from acetylene.

 

Answer:

 

1)    NaNH2

2)    CH3CH2Br

3)    NaNH2

4)    CH3CH2CH2Br

 

Section:

 

 

5.15

 

79)

 

Describe a sequence of reactions by which     can be straightforwardly prepared from 1-butyne.

 

Answer:

 

1)    NaNH2

2)    CH3CH2Br

3)    HgSO4, H2O, H2SO4

 

Section:

 

 

5.15

 

80)

 

Describe a sequence of reactions by which cis-2-pentene could be prepared from acetylene.

 

Answer:

 

1)    NaNH2

2)    CH3CH2Br

3)    NaNH2

4)    CH3Br

5)    H2, Lindlar’s catalyst

 

Section:

 

 

5.15

 

81)

 

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

 

 

 

1. A)

 

CH2CH2 + HCCH

 

1. B)

 

CH3CH2CCH

 

1. C)

 

HCCBr

 

1. D)

 

HCCCH2CH2Br

 

1. E)

 

CH3CCCH3

 

Answer:

 

B

 

Section:

 

 

5.15

 

82)

 

What is the structure of the monomer from which the following polymer is made?

 

 

 

1. A)

 

CH3CH3

 

1. B)

 

CH2CH2

 

1. C)

 

CH3CHCH2

 

1. D)

 

CH2CHCHCH2

 

1. E)

 

CH3CHCHCH3

 

Answer:

 

E

 

Section:

 

 

5.16

 

83)

 

What is the structure of the monomer from which the following polymer is made?

 

 

 

1. A)

 

I

 

1. B)

 

II

 

1. C)

 

III

 

1. D)

 

IV

 

1. E)

 

V

 

Answer:

 

B

 

Section:

 

 

5.16

 

84)

 

Which of the following addition polymers results from the reaction below?

nCF2CF2  ?

 

 

1. A)

 

[CF-CF]n

 

1. B)

 

[CF3-CF3]n

 

1. C)

 

[-CF2-CHCHCF2-]n

 

1. D)

 

[-CF2-CF2-]n

 

1. E)

 

[-CF2CF2-]n

 

Answer:

 

D

 

Section:

 

 

5.16

 

85)

 

Which of the following species can best serve as a radical initiator for radical polymerization?

 

1. A)

 

ROH

 

1. B)

 

ROR

 

1. C)

 

ROOR

 

1. D)

 

RCOOR

 

1. E)

 

RCOOH

 

Answer:

 

C

 

Section:

 

 

5.16

 

86)

 

Which of the following is the first chain propagating step in the radical polymerization of ethylene using a peroxide initiator?

 

 

1. A)

 

ROOR + CH2CH2 → ROCH2CH2OR

 

 

1. B)

 

∙

RO∙ + CH2CH2 → ROCH2CH2

 

 

1. C)

 

RO∙ + CH2CH2 → ROCHCH2 + H∙

 

 

1. D)

 

∙         ∙

ROOR + CH2CH2 → 2 ROH + CHCH

 

 

1. E)

 

∙       ∙

2RO∙ + CH2CH2 → 2 ROH + CHCH

 

Answer:

 

B

 

Section:

 

 

5.16

 

87)

 

List the three phases in the mechanism of chain-growth polymerization.

 

Answer:

 

1. Initiation
2. Propagation
3. Termination

 

Section:

 

 

1.2

 

88)

 

Show the mechanism for the formation of a segment of polystyrene containing two molecules of styrene and initiated by hydrogen peroxide.

 

Answer:

 

 

 

 

Section:

 

 

5.16

 

89)

 

Provide a mechanism to show how H2CC(CH3)2 is polymerized using BF3 as the initiatior.

 

Answer:

 

 

 

 

Section:

 

 

5.16