Practice Problems Series 1 Ch1-Ch6
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Organic Chemistry
Carey/Giuliano
9th edition
Chapter 1
Copyright © 2014 The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Question 1
What is the electronic configuration of carbon?
A) 1s2 2s2 2px2
B) 1s2 2s2 2px1 2py
12pz0
C) 1s2 2s2 2px12py
12pz1
D) 1s2 1px1 1py
12s2
Question 2
K+ is isoelectronic with what other element?
A) Ar
B) Ca
C) Na
D) Rb
Question 3
Select the correct Lewis structure for methyl
fluoride (CH3F).
A) B)
C) D)
Question 4
What is the correct Lewis structure of
formaldehyde (H2C=O)?
A) B)
C) D)
Question 5
In which of the compounds below is the d+ for
H the greatest?
A) CH4
B) NH3
C) SiH4
D) H2O
Question 6
Which of the following bonds have the greatest
dipole moment?
A) B)
C) D)
Question 7
Which of the following bonds have the greatest
dipole moment?
A) B)
C) D)
Question 8
How many constitutional isomers have the
formula C3H7Cl?
A) one
B) two
C) three
D) four
Question 9
The bond-line representation for
(CH3)2CHCH2CH2CHBrCH3 is
A) B)
C) D)
Question 10
How many constitutional alcohol isomers have
the molecular formula C4H10O?
A) two
B) three
C) four
D) five
Question 11
What is the formal charge of the sulfur atom in
the Lewis structure?
A) -1
B) 0
C) +1
D) +2
Question 12
What is the formal charge of the sulfur atom in
the Lewis structure given at the right?
A) -2
B) -1
C) +1
D) +2
Question 13
Which resonance structure contributes more to
the hybrid?
A) B)
Question 14
What is the molecular shape of the carbons of
acetylene (HCCH)?
A) tetrahedral
B) bent
C) trigonal planar
D) linear
Question 15
Select the chemical equation that depicts the
correct movement of electrons in the
reaction of ammonia with hydrogen chloride.
A) B)
C) D)
Question 16
Which of the following is most likely to have
ionic bonds?
A) HCl
B) Na2O
C) N2O
D) NCl3
Question 17
In which of the following is oxygen the positive
end of the bond dipole?
A) O-F
B) O-N
C) O-S
D) O-H
Question 18
The total number of unshared pairs of
electrons in the molecule is:
A) 0
B) 1
C) 2
D) 3
Question 19
Which of the following contains a triple bond?
A) SO2
B) HCN
C) C2H4
D) NH3
Answer Key – Chapter 1
1. B
2. A
3. C
4. C
5. D
6. D
7. A
8. B
9. A
10. C
11. C
12. D
13. B
14. D
15. C
16. B
17. A
18. D
19. B
Organic Chemistry
Carey/Giuliano
9th edition
Chapter 2
Copyright © 2014 The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Question 1
In the most stable conformation of butane,
what is the dihedral angle between the
methyl groups?
A) 109.5°
B) 60°
C) 120°
D) 180°
Question 2
How many hydrogens are in a molecule of
isobutane?
A) 6
B) 8
C) 10
D) 12
Question 3
How many isomeric hexanes exist?
A) 2
B) 3
C) 5
D) 6
Question 4
What is the approximate C-C-C bond angle of
propane (CH3CH2CH3)?
A) 90°
B) 109.5°
C) 120°
D) 180°
Question 5
The correct IUPAC name for 2-ethylpentane is:
A) n-heptane
B) 2-methylpentane
C) 2-methylhexane
D) 3-methylhexane
Question 6
The correct structure of 3-ethyl-2-
methylpentane is:
A) B)
C) D)
Question 7
In 3-ethyl-2-methylpentane, carbon #3 (marked by a star) is classified as:
A) primary (1°)
B) secondary (2°)
C) tertiary (3°)
D) quaternary (4°)
Question 8
The second carbon of 2,2-dimethylbutane
(marked by a star) is classified as:
A) primary (1°)
B) secondary (2°)
C) tertiary (3°)
D) quaternary (4°)
Question 9
What is the correct IUPAC name for the
compound on the right?
A) 1-ethyl-2-methylcyclohexane
B) 2-ethyl-1-methylcyclohexane
C) 1-methyl-2-ethylcyclohexane
D) 2-methyl-1-ethylcyclohexane
Question 10
What is the correct IUPAC name for the
cycloalkane on the right?
A) undecane
B) cyclodecane
C) cycloundecane
D) cyclododecane
Question 11
Arrange octane, 2,2,3,3-tetramethylbutane and 2-methylheptane in order of increasing boiling point.
A) 2,2,3,3-tetramethylbutane < octane < 2- methylheptane
B) octane < 2-methylheptane < 2,2,3,3- tetramethylbutane
C) 2,2,3,3-tetramethylbutane < 2- methylheptane < octane
D) 2-methylheptane < 2,2,3,3- tetramethylbutane < octane
Question 12
To carry out the reaction shown below we need:
CH3OH H2C=O
A) an oxidizing agent
B) a reducing agent
Question 13
What is the hybridization of the starred carbon
in humulene (shown)?
A) sp
B) sp2
C) sp3
D) 1s2 2s2 2p2
Question 14
What is the hybridization of the starred carbon
of geraniol?
A) sp
B) sp2
C) sp3
D) 1s2 2s2 2p2
Question 15
The carbon skeleton shown at the bottom right accounts for 9 carbon atoms. How many
other isomers of C10H22 that have 7 carbons in their longest continuous chain can be generated by adding a single carbon to various positions on this skeleton? A) 2
B) 3
C) 4
D) 5
Question 16
How many primary carbons are in the molecule
shown at the bottom right?
A) 2
B) 3
C) 4
D) 5
Question 17
Which one contains the greatest number of
tertiary carbons?
A) 2,2-dimethylpropane
B) 3-ethylpentane
C) sec-butylcyclohexane
D) 2,2,5-trimethylhexane
Question 18
The systematic name for a sec-butyl group is:
A) 1-methylpropyl
B) 2-methylpropyl
C) 1,1-dimethylethyl
D) 1,2-dimethylethyl
Question 19
Which of the following is a 3-methylbutyl group?
A) CH3CH2CH2CH2CH2-
B) (CH3)2CHCH2CH2-
C) (CH3CH2)2CH-
D) (CH3)3CCH2-
Question 20
Which alkane has the highest boiling point?
A) hexane
B) 2,2-dimethylbutane
C) 2-methylpentane
D) 2,3-dimethylbutane
Answer Key – Chapter 2
1. D
2. C
3. C
4. B
5. D
6. B
7. C
8. D
9. A
10. C
11. C
12. A
13. C
14. B
15. B
16. C
17. C
18. A
19. B
20. A
Organic Chemistry
Carey/Giuliano 9th edition Chapter 3
Copyright © 2014 The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Question 1 What is the relationship between the Newman
representations shown? A) identical B) constitutional isomers C) different conformations of the same compound D) stereoisomers
Question 2 What is the relationship between the Newman
representations shown? A) identical B) constitutional isomers C) different conformations of the same compound D) stereoisomers
Question 3
Select the least stable conformation of ethylene glycol.
A) B) C) D)
Question 4
Select the most stable conformation of butanoic acid.
A) B) C) D)
Question 5
Which compound has the greatest torsional strain in the planar conformation?
A) cyclopropane B) cyclobutane C) cyclopentane D) cyclohexane
Question 6
Rank the conformations of cyclohexane in order of decreasing stability.
A) chair > half-chair > twist-boat B) chair > twist-boat > half-chair C) twist-boat > half-chair > chair D) half-chair > twist-boat > chair
Question 7
The most stable conformation of cis-1-tert-butyl-4-methylcyclohexane has
A) both groups equatorial B) both groups axial C) the tert-butyl group axial and the methyl
equatorial D) the tert-butyl group equatorial and the
methyl axial
Question 8
The most stable conformation of trans-1-isopropyl-3-methylcyclohexane is:
A) B) C) D)
Question 9 What is the relationship between the two chair
conformations below? A) conformational isomers B) constitutional isomers C) different compounds D) stereoisomers
Question 10
What is the relationship between the two cyclohexane chairs below?
A) conformational isomers B) constitutional isomers C) stereoisomers D) different compounds
Question 11
Which of the following statements is not true concerning the chair-chair interconversion of
trans-1,2-diethylcyclohexane? A) An axial group will be changed into the
equatorial position. B) The energy of repulsions present in the
molecule will be changed. C) Formation of the cis substance will result. D) One chair conformation is more stable
than the other
Question 12
Which of the listed terms best describes the relationship between the methyl groups in the chair conformation of the substance shown?
A) eclipsed B) trans C) anti D) gauche
Question 13
Which of the following has an equatorial methyl group in its most stable conformation?
A) B) C) D)
Question 14
The structure shown is the carbon skeleton of adamantane, a hydrocarbon having a
structure that is a section of the diamond lattice. Adamantane is:
A) bicyclic B) tricyclic C) tetracyclic D) pentacyclic
Question 15
Which structure has the most strain? A) the eclipsed conformation of ethane B) the gauche conformation of butane C) the boat conformation of cyclohexane D) the skew boat conformation of
cyclohexane
Question 16 What is the IUPAC name for the compound
represented by the Newman projection? A) 1-tert-Butyl-1-isopropylethane B) 1-tert-Butyl-3-methylbutane C) 2-isopropyl-3,3-dimethylbutane D) 2,2,3,4-tetramethylpentane
Question 17 Which one of the following statements is true? A) Van der Waals strain in cis-1,2-
dimethylcyclopropane is the principal reason for its decreased stability relative to the trans
isomer. B) Cycloalkanes larger than cyclodecane rarely
occur naturally because they are too strained. C) One mole of cyclohexane gives off less heat
on being burned in air than one mole of any other cycloalkane.
D) The principal source of strain in the gauche conformation of butane is torsional strain.
Question 18
Which of the following statements best describes the most stable conformation of
trans-1,3-dimethylcyclohexane? A) Both methyl groups are axial. B) Both methyl groups are equatorial. C) One methyl groups is axial, the other
equatorial. D) The molecule is severely strained and
cannot exist.
Question 19 What is the relationship between the two
structures shown? A) Constitutional isomers B) Stereoisomers C) Different drawings of the same conformation of the same compound. D) Different conformations of the same
compound.
Question 20 The most stable conformation of the compound
to the right has A) an axial methyl group and an axial ethyl group. B) an axial methyl group and an equatorial ethyl group. C) an equatorial methyl group and an
equatorial ethyl group. D) an equatorial methyl group and an axial
ethyl group.
Answer Key – Chapter 3 1. C 2. B 3. C 4. B 5. D 6. B 7. D 8. B 9. A 10. C
11. C 12. D 13. D 14. B 15. C 16. D 17. A 18. C 19. A 20. D
Organic Chemistry
Carey/Giuliano 9th edition Chapter 4
Copyright © 2014 The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Question 1 Name the compound on the right according to
the IUPAC system. A) 4-bromo-5-ethyl-2-methylheptane B) 4-bromo-3-ethyl-6-methylheptane C) 4-bromo-5-diethyl-2-methylpentane D) 4-bromo-3-ethyl-6-dimethylhexane
Question 2 Name the compound on the right according to
the IUPAC system. A) 3,4-dimethyl-2-hydroxypentane B) 2,3-dimethyl-4-pentanol C) 3,4-dimethyl-2-pentanol D) 2,3-dimethylpentyl-2-alcohol
Question 3 Name the compound on the right according to
the IUPAC system. A) trans-2-methylhydroxypentanol B) trans-2-methylcyclopentanol C) cis-2-methylhydroxypentanol D) cis-2-methylcyclopentanol
Question 4
What type of alcohol is 2-methyl-3-pentanol? A) primary (1°) B) secondary (2°) C) tertiary (3°) D) quaternary (4°)
Question 5
What is the product of the reaction of 2-methylcyclohexanol with HBr?
A) B) C) D)
Question 6
What product will be isolated from the reaction of 2-pentanol with HBr?
A) B) C) D)
Question 7
What is the rate-determining step in the reaction of cyclobutanol with HCl?
A) protonation of the OH group B) attack of the bromide on the carbocation C) simultaneous formation of the C-Br bond
and the breaking of the C-OH bond D) carbocation formation
Question 8
What are the best conditions to convert 1-pentanol into 1-chloropentane?
A) HCl, heat B) SOCl2, pyridine C) Cl2, CCl4 D) NaCl, H2O, heat
Question 9
Select the most stable carbocation. A) B) C) D)
Question 10
How many monochlorination products do you expect to obtain from the chlorination of
2-methylbutane? A) two B) three C) four D) five
Question 11
The step shown below is a _____________ step of the free-radical chlorination of
chloromethane. A) initiation B) propagation C) chain-terminating D) bond cleavage
Question 12
What is the major product of the radical bromination of 1-tert-butylcyclopentane?
A) B) C) D)
Question 13
Which one of the following reacts with HBr at the fastest rate?
A) B) C) D)
Question 14
Which of the following is the least able to serve as a nucleophile in a chemical reaction?
A) Br- B) OH- C) NH3 D) CH3
+
The species shown below represents _____ of the reaction between isopropyl alcohol and
hydrogen bromide. A) the alkyloxonium ion intermediate B) the transition step of the bimolecular
proton transfer C) the transition state of the attack of the
nucleophile on the carbocation D) the transition state of the unimolecular
dissociation
Question 15
Question 16 For the free-radical reaction below, light is
involved in which of the following reaction steps? A) Initiation only B) Propagation only C) Termination only D) Initiation and propagation
Question 17
How many monohalogenation products are possible? (Do not consider stereoisomers.)
A) 2 B) 3 C) 4 D) 5
Question 18
Which one of the following would not be a satisfactory method for the preparation of a
primary alkyl halide? A) Treatment of 1-hexanol with PBr3. B) Treatment of 4-methyl-1-pentanol with SOCl2. C) Treatment of 2-methylbutane with Br2 (light,
heat). D) Treatment of 1-decanol with NaBr and H2SO4
(heat).
Question 19 Which of the following best describes a mechanistic
feature of the free-radical bromination (Br2, light) of 2-methylpropane?
A) The initiation step involves cleavage of a C-H bond.
B) The free-radical (CH3)3C· is produced in one propagation step and reacts with Br2 in another.
C) The reaction is characterized by the homolytic cleavage of the C-Br bond.
D) The reaction is concerted; i.e., it occurs in a single step.
Question 20
An alkane with a molecular formula of C8H18 reacts with Cl2 in the presence of light and
heat to give a single monochloride C8H17Cl. What is the most reasonable structure for the starting alkane?
A) CH3CH2CH2CH2CH2CH2CH2CH3 B) (CH3CH2)2CHCH2CH2CH3 C) (CH3)2CHCH2CH2CH(CH3)2 D) (CH3)3CC(CH3)3
Answer Key – Chapter 4 1. A 2. C 3. B 4. B 5. D 6. B 7. D 8. B 9. C 10. C
11. B 12. D 13. C 14. D 15. D 16. A 17. C 18. C 19. B 20. D
Organic Chemistry
Carey/Giuliano
9th edition
Chapter 5
Copyright © 2014 The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Question 1
Name the alkene below according to the
IUPAC system.
A) 2-bromo-5-heptane
B) 6-bromo-2-heptene
C) 2-bromo-5-heptene
D) 5-bromo-2-heptene
Question 2
How many alkenes will produce 3-ethylpentane
on catalytic hydrogenation?
A) 2
B) 3
C) 4
D) 5
Question 3
What is the major product of the dehydration of
2-methylcyclohexanol?
A) 1-methylcyclohexene
B) 2-methylcyclohexene
C) 3-methylcyclohexene
D) cyclohexene
Question 4
The major product of the dehydration of 1-
phenyl-2-propanol is
A) B)
C) D)
Question 5
Which alkene can have cis/trans stereoisomers?
A) B)
C) D)
Question 6
Of the compounds with the formula C3H5Cl,
which one has cis/trans isomers?
A) 1-chloropropene
B) 2-chloropropene
C) 3-chloropropene
D) all of them
Question 7
Assign the configuration of the alkenes below as Z or E, respectively.
A) E,E
B) E,Z
C) Z,Z
D) Z,E
Question 8
Rank the following alkenes in order of decreasing heat of combustion:
A) 3 > 1 > 2
B) 2 > 3 > 1
C) 1 > 2 > 3
D) 2 > 1 > 3
Question 9
The dehydration of 2-methyl-2-propanol cannot
be accomplished by using which of the
following reagents?
A) H2SO4
B) H3PO4
C) HCl
D) KHSO4
Question 10
What is the major product in the reaction of 2-
methyl-2-butanol with H2SO4 at 80°C?
A) B)
C) D)
Question 11
The reaction of 2-bromobutane with
KOCH2CH3 in ethanol produces trans-2-
butene. If the concentration of both
reactants is doubled, what would be the
effect on the rate of the reaction?
A) halve the rate
B) double the rate
C) quadruple the rate
D) no effect on the rate
Question 12
Which would react with KOCH2CH3 in ethanol
faster?
A) cis-2-tert-butylcyclohexyl bromide
B) trans-2-tert-butylcyclohexyl bromide
Question 13
Which would react with KOC(CH3)3/(CH3)3COH
faster?
A) cis-3-tert-butylcyclohexyl bromide
B) trans-3-tert-butylcyclohexyl bromide
Question 14
How many alkenes would you expect to be
formed from the E2 elimination of
3-bromo-2-methylpentane?
A) 2
B) 3
C) 4
D) 5
Question 15
Of the isomeric alcohols having the molecular
formula C5H12O, which one will undergo
acid-catalyzed dehydration most readily?
A) 2-pentanol
B) 2-methyl-1-butanol
C) 2-methyl-2-butanol
D) 3-methyl-2-butanol
Question 16
The heat of hydrogenation of cis-2-pentene is 117 kJ/mol. For which one of the following
alkenes is the heat of hydrogenation 126 kJ/mol?
A) 1-pentene
B) trans-2-pentene
C) 2-methyl-1-butene
D) 2,3-dimethyl-2-butene
Question 17
The molecular formula of b-Carotene is C40H56.
On catalytic hydrogenation, b-carotene is
converted to a saturated hydrocarbon of
molecular formula C40H78. How many rings
does b-carotene contain?
A) none
B) one
C) two
D) three
Question 18
Which one of the following best describes a mechanistic feature of the reaction of
3-bromopentane with sodium ethoxide?
A) The reaction occurs in a single step which is bimolecular.
B) The reaction occurs in two steps, both of which are unimolecular.
C) The rate-determining step involves the formation of the carbocation (CH3CH2)2CH+.
D) The carbon-halogen bond breaks in a rapid step that follows the rate-determining step.
Question 19
Which of the following statements is false?
A) tert-Butyl alcohol reacts with sodium faster than 1-butanol.
B) tert-Butyl alcohol reacts with hydrogen bromide faster than sec-butyl alcohol.
C) tert-Butyl alcohol undergoes acid-catalyzed dehydration faster than sec-butyl alcohol does.
D) tert-Butyl alcohol undergoes E2 elimination faster than tert-butyl fluoride does.
Question 20
The Zaitsev rule can be used to predict the major product of which one of the following
reactions?
A) 2-methylbutane + Cl2 (heat)
B) 2-methyl-2-butanol + Na
C) 2-methyl-2-butanol with HCl
D) 2-bromo-2-methylbutane + NaOCH2CH3 in ethanol (heat)
Question 21
Which reaction would be most likely to proceed
by an E1 mechanism?
A) 2-chloro-2-methylbutane + NaCH2CH3 in
ethanol (heat)
B) 1-bromo-2-methylbutane + KOC(CH3)3 in
DMSO
C) 2-bromo-2-methylbutane in ethanol
(heat)
D) 2-methyl-2-butanol + K
Question 22
Which one of the following groups has the highest rank when precedence is assigned
according to the Cahn-Ingold-Prelog system?
A) -CH2Cl
B) -CH=O
C) -C(CH3)3
D) CH2NH2
Question 23
How many alkenes, including stereoisomers,
contain a tert-butyl group and have the
molecular formula C7H14?
A) 3
B) 4
C) 5
D) 6
Answer Key – Chapter 5
1. B
2. A
3. A
4. C
5. D
6. A
7. A
8. D
9. D
10. B
11. C
12. A
13. B
14. B
15. C
16. A
17. C
18. A
19. A
20. D
21. C
22. A
23. B
Organic Chemistry
Carey/Giuliano
9th edition
Chapter 6
Copyright © 2014 The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Question 1
Rank the following alkenes in order of
decreasing heat of hydrogenation.
A) 1 > 3 > 2
B) 3 > 2 > 1
C) 2 > 3 > 1
D) 1 > 2 > 3
Question 2
Which of the alkenes below will produce 2-
methylbutane on catalytic hydrogenation?
A) 1 and 3
B) 1, 2 and 3
C) 2 and 4
D) 2, 3 and 4
Question 3
Which carbocation forms when 3-methyl-2-
pentene is protonated?
A) B)
Question 4
Which alkene has the lowest heat of
hydrogenation?
A) B)
C) D)
Question 5
The reaction of 3-methyl-1-butene with HBr
produces 2-bromo-3-methylbutane and
which other alkyl halide?
A) B)
C) D)
Question 6
What is the product of the reaction of 1-
methylcyclohexene with HCl?
A) B)
C) D)
Question 7
What is the correct IUPAC name of the
compound isolated from the reaction of
2-methyl-2-pentene with HBr in the
presence of peroxides?
A) 3-bromo-4-methylpentane
B) 3-bromo-2-methylpentane
C) 2-bromo-2-methylpentane
D) 2,3-dibromo-2-methylpentane
Question 8
The product isolated from the acid-catalyzed
hydration of cis-3-methyl-2-pentene is:
A) 2-ethyl-2-butanol
B) 2-ethyl-1-butanol
C) 3-methyl-2-pentanol
D) 3-methyl-3-pentanol
Question 9
Which alkene will undergo acid-catalyzed
hydrolysis at the fastest rate?
A) B)
C) D)
Question 10
What is the product of the addition of Br2 to
cyclopentene?
A) B)
C) D)
Question 11
Arrange the alkenes in order of decreasing rate of reaction toward bromine addition:
2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene
A) 2-methyl-1-butene > 3-methyl-1-butene > 2-methyl-2-butene
B) 3-methyl-1-butene > 2-methyl-1-butene > 2-methyl-2-butene
C) 2-methyl-2-butene > 2-methyl-1-butene > 3-methyl-1-butene
D) 2-methyl-2-butene > 3-methyl-1-butene > 2-methyl-1-butene
Question 12
The ozonolysis of 2,4-dimethyl-2-pentene will
produce:
A) B)
C) D)
Question 13
Which combination of reagents is the best choice for carrying
out the conversion shown?
A) 50% water - 50% sulfuric acid
B) 1. H2SO4
2. H2O, heat
C) 1. O3
2. H2O, Zn
D) 1. BH3-THF
2. H2O2, NaOH
Question 14
Which one of the following terms best applies
to the hydrogenation of an alkene in the
presence of finely divided platinum? (in
ethanol as solvent)
A) anti addition
B) Concerted reaction
C) heterogeneous catalysis
D) endothermic reaction
Question 15
Which reagent reacts with an alkene to
produce an epoxide?
A) B)
C) D)
Question 16
Hydroboration-oxidation of which one of the
following yields a primary alcohol as the
major product?
A) B)
C) D)
Question 17
Which one of the following is not stereospecific?
A) reaction of cis-2-butene with peroxyacetic acid
B) hydroboration-oxidation of 1- methylcyclopentene
C) addition of Br2 to trans-2-pentene
D) addition of HBr to cis-2-butene in the presence of peroxides
Question 18
Which alkene reacts with HCl (electrophilic
addition) at the fastest rate?
A) B)
C) D)
Question 19
Which one of the following outlines the best synthesis of trans-2-chlorocyclohexanol?
A) Heat a mixture of cyclohexanol and Cl2 to 400oC.
B) 1. Treat cyclohexene with HCl;
2. Treat product of reaction 1 with peroxyacetic acid.
C) 1. Hydrogenation of cyclohexene in the presence of Pt;
2. Treat product of reaction 1 with Cl2 in H2O.
D) 1. Treat bromocyclohexane with KOC(CH3)3 in DMSO;
2. Treat product of reaction 1 with Cl2 in water.
Answer Key – Chapter 6
1. A
2. A
3. B
4. C
5. B
6. A
7. B
8. D
9. D
10. A
11. C
12. B
13. D
14. C
15. C
16. A
17. D
18. C
19. D