General Chemistry, 11e (Petrucci)
Chapter 27 Reactions of Organic Compounds
1) In a substitution reaction an atom, an ion or a group in one molecule is replaced by another atom, ion
or group.
2) Molecules add across multiple bonds in another molecule in addition reactions.
3) Organic reactions in which atoms or groups that are bonded to adjacent carbon atoms are eliminated
are called elimination reactions.
4) Nucleophiles are electron poor atoms, ions or groups.
5) SN2 reactions are nucleophilic substitution reactions for which the rate determining step is
bimolecular.
6) Synthesis of alkanes from alkyl halides is a typical example of E2 reaction.
7) Reactions between alkanes and HX compounds are typical examples of addition reactions.
8) Electrophilic substitution reactions are typical reactions of aromatic compounds.
9) The alkanes are known for their reactivity.
10) The step reaction polymerizations are fast polymerization reactions.
11) For which type of reaction is the following an example?
A) substitution
B) elimination
C) polymerization
D) rearrangement
E) addition
12) Which of the following trends in nucleophilicity are correct?
I) Everything else being equal, a negatively charged nucleophile will react faster than a neutral one.
II) Generally, species containing elements of high electronegativity are good nucleophiles.
III) Anionic nucleophiles are more reactive in polar and aprotic solvents than in polar and protic
solvents.
IV) Generally, nucleophilicity is increasing with the increase in size of an atom.
V) Bulky groups adjacent to the nucleophilic atom enhance the nucleophilicity and reactivity of the
species.
A) I), II), III), and V)
B) II), III), IV) and V)
C) I), II) and IV)
D) II), III) and V)
E) III), IV) and V)
13) We can promote SN2 over SN1 reactions if we:
I) use a substrate that gives a primary carbocation and not tertiary carbocation
II) use a sterically hindered substrate
III) use a polar protic solvent
A) I)
B) II)
C) III)
D) I) and III)
E) II) and III)
14) Arrange the following in the order of decreasing nucleophilicity:
H2N–, HO–, HCOO–, CH3O–
A) H2N– > HO– > HCOO– > CH3O–
B) H2N– > CH3O– > HO– > HCOO–
C) H2N– > HO– > CH3O– > HCOO–
D) HO– > H2N– > CH3O– > HCOO–
E) CH3O– > HO– > H2N– > HCOO–
15) Arrange the following carbocations in order of decreasing stability:
A) A > B > C
B) C > B > A
C) B > C > A
D) C > A > B
E) B > A > C
16) Which of the following statements correctly describe SN2 and SN1 reactions?
I) SN2 reactions proceed with retention of configuration.
II) SN1 reactions prefer polar protic solvents.
III) SN1 reactions can produce racemic products.
IV) SN2 reactions are promoted in the presence of a substrate that produces a very stable carbocation.
V) SN1 reactions have a unimolecular rate-determining step.
A) I), II) and V)
B) II), III), and IV)
C) III), IV) and V)
D) II), III) and V)
E) I), III), and IV)
17) The following can be said about the reaction profile of an SN1 reaction:
I) The rate determining step is the formation of a carbocation.
II) The reaction profile has one transition state.
III) The slow step is the first transition state.
IV) The second step is attack of nuleophile on carbocation.
V) The reaction proceeds in a polar aprotic solvent.
A) I), III), and IV)
B) I), II) and IV)
C) II), III) and IV)
D) I), II) and V)
E) II), IV) and V)
18) Find the combination of conditions that are the best for SN2 reactions.
A) The substrate is a tertiary alkyl iodide, solvent is aprotic, polar and the nucleophile is a strong base.
B) The substrate is a primary alkyl iodide, solvent is aprotic, polar and the nucleophile is a strong base.
C) The substrate is a primary alkyl fluoride, solvent is protic, polar and the nucleophile is a strong base.
D) The substrate is a primary alkyl iodide, solvent is non-polar and the nucleophile is a weak base.
E) The substrate is a tertiary alkyl iodide, solvent is non-polar and the nucleophile is a strong base.
19) Finish the sentence:
“Elimination reactions…
A) …can follow two different mechanisms.”
B) …do not compete with other reaction types.”
C) …usually give a saturated product.”
D) …always give only one product.”
E) …have only one mechanistic path.”
20) Which of the following steps can be found in E1 reaction mechanism?
I) formation of a carbocation
II) attack of the base and removal of a proton from carbocation
III) attack of a nucleophile
IV) formation of a carboanion
A) I) and II)
B) only II)
C) I) and III)
D) III) and IV)
E) only III)
21) Arrange the following alkenes according to their increasing stability:
A) A < B < C < D
B) B < C < A < D
C) B < A < C < D
D) C < B < A < D
E) C < A < B < D
22) Hyperconjugation is best described as:
A) an interaction between the orbitals on a substrate and orbitals on a nucleophile
B) an interaction between σ bonds and π network
C) a resonance structure with separated charges
D) an interaction between two π networks
E) an electrostatic interaction between an electrophile and a nucleophile
23) What is the major product in the reaction between 2-bromo-3-methylbutane and KOtBu in ethanol?
A)
B)
C)
D)
E)
24) The rate of E2 reaction between an alkyl halide RX and a base B is given by the following expression
(k is a rate constant):
A) k[RX]
B) k[B]
C) k[RX][B]
D) k[RX]2
E) k[RX]2[B]
25) In which of the following reactions can alcohol participate?
I) oxidation reactions
II) elimination reactions
III) amide synthesis
IV) peptide synthesis
V) ester synthesis
A) I), III) and V)
B) I), II) and V)
C) II), III) and V)
D) I), II) and IV)
E) II), III) and IV)
26) What is a dehydration reaction?
A) Dehydration is the elimination of water molecule from an alcohol molecule to produce alkene.
B) A dehydration reaction is the removal of one equivalent of H2 from an alkane to produce alkene.
C) A dehydration reaction is one of the steps in chain-reaction polymerization.
D) A dehydration reaction is the removal of crystalline water.
E) A dehydration reaction is the deprotonation of a substrate with a strong base in E2 mechanism.
27) Which of the following roles can alcohols have in organic reactions?
I) electrophile
II) solvent
III) base
IV) substrate
V) acid
A) II), III) and IV)
B) I), II), and III)
C) I), III) and V)
D) II), III) and V)
E) II), IV) and V)
28) What product would you expect to obtain from a reaction between one isomer of 3-methyl-1-pentanol
and HI?
A) a substitution product
B) only one elimination product
C) a substitution product with inversion of configuration
D) two elimination products
E) a racemic mixture of substitution products
29) Which of the following is an unsymmetrical reagent?
A) Cl2
B) H2O
C) H2O and HCl
D) HCl
E) I2
30) Markovnikof’s rule predicts that when HBr is added to an unsymmetrical alkene or alkyne, the H
atom will add to which carbon atom?
A) the carbon with the fewest attached hydrogens
B) the carbon with the Br
C) the carbon with the most attached hydrogens
D) the carbon next to the double or triple bond
E) HBr does not react with unsymmetrical alkenes or alkynes
31) Which of the following could be added across carbon-carbon multiple bonds?
I) H2SO4
II) H2
III) H2O
IV) NO2
V) HBr
A) II), III), and V)
B) II), III), and IV)
C) I), III), and V)
D) I), III), and IV)
E) I), II), and III)
32) From the following table select appropriate starting material and reagents required for the synthesis
of 2-methyl-2-propanol (tert-butanol):
Starting materials: Reagents
A) I) H2/Pt
B) II) H2O/ H2SO4
C) III) HBr
A) starting material B) and reactants II)
B) starting material C) and reactants I)
C) starting material A) and reactants II)
D) starting material A) and reactants III)
E) starting material B) and reactants I)
33) Which of the following steps would you expect to occur in the addition reaction mechanism?
I) electrophilic attack on the unsaturated bond
II) formation of carboanion
III) formation of carbocation
IV) nucleophilic attack on the carbocation
V) elimination of a base
A) I), III), and IV)
B) I), II), and V)
C) II), III) and IV)
D) III), IV) and V)
E) II), IV) and V)
34) A hydrocarbon has a molecular weight 56 g/mol and contains 85.7% carbon. It easily adds one mol of
HBr to produce a chiral alkyl bromide. Which of the following structures could be the hydrocarbon?
A)
B)
C)
D)
E)
35) Which of the following groups is a meta director during electrophilic aromatic substitution?
A) –NH2
B) –OCH3
C) –Br
D) –C≡N
E) –OCOC2H5
36) Find a group that is a ortho,para director in electrophilic aromatic substitution.
A) –NO2
B) –SO3H
C) –OH
D) –COOH
E) –COOCH3
37) What is arenium ion?
A) a carbocation formed after the electrophilic attack on the benzene ring
B) a carbocation formed from a molecule containing an arene ring
C) a carbocation formed during the elimination reaction from an aromatic molecule
D) a carboanion formed from deprotonation of benzene ring
E) a carboanion formed after nucleophilic attack on the benzene ring
38) During the nitration of a benzene ring in a mixture of HNO3 and H2SO4 the following species reacts
as an electrophile:
A) H3O+
B) H3SO4+
C) H2NO3+
D) H+
E) NO2+
39) Which of the following compounds could be used as catalysts in halogenation of benzene?
I) AlCl3
II) NaCl
III) FeBr3
IV) MgCl2
V) PbCl2
A) I) and V)
B) II) and III)
C) II) and IV)
D) I) and III)
E) III) and V)
40) Which of the following mechanistic steps do you expect in bromination of benzene with Br2 and
FeBr3 as a catalyst?
I) formation of Br+[FeBr4]–
II) attack of [FeBr4]– on benzene ring
III) formation of arenium ion
IV) deprotonation of arenium ion
V) nucleophilic attack of Br+
A) I), III), and IV)
B) I), II), and IV)
C) II), III), and V)
D) III), IV), and V)
E) II), IV), and V)
41) Nitration of aromatic compound I with HNO3/H2SO4 theoretically can give four different products
(A – D). In your opinion, which one(s) is(are) formed?
Compound I:
Possible products:
A) products A and C
B) products A and D
C) only product B
D) products C and D
E) only product C
42) The chlorination of benzaldehyde is producing:
A) m-chlorobenzaldehyde
B) a mixture of o and p– chlorobenzaldehyde
C) o -chlorobenzaldehyde
D) p-chlorobenzaldehyde
E) a mixture of m– and p-chlorobenzaldehyde
43) H3C∙ + ∙Cl → H3C—Cl is an example of:
A) polymerization
B) neutralization reaction
C) termination step in alkane chlorination
D) addition reaction
E) reforming reaction
44) Arrange the following radicals in the order of increasing stability:
A) B < A < C
B) C < A < B
C) A < B < C
D) C < B < A
E) B < C < A
45) Which of the following steps are a part of chain reaction during alkane substitution?
I) propagation
II) initiation
III) competition
IV) dehalogenation
V) termination
A) I), II) and V)
B) I), III) and V)
C) II), III) and V)
D) I), II) and IV)
E) III), IV) and V)
46) The initiation step in chain reaction for alkene substitution produces:
A) free halogen radicals
B) free alkyl radicals
C) both free halogen and alkyl radicals
D) free halonium ions
E) free halide ions
47) Chain reaction polymerization is typical for:
A) monomers with carbon-carbon double bonds
B) monomers with carbon oxygen double bonds
C) monomers containing aromatic rings
D) monomeric alkanes
E) monomeric alcohols
48) What are the three characteristic steps in a chain-reaction polymerization?
A) initiation, elongation and termination
B) initiation, propagation and termination
C) racemization, propagation and quenching
D) propagation, formation and termination
E) breaking, elongation and quenching
49) Which of the following statements correctly describe the step-reaction polymerization?
I) It is also called condensation polymerization.
II) It produces polymers of moderately high molecular masses.
III) It requires that monomers have functional groups that can join together.
IV) This type of polymerization is fast.
V) It is accompanied with the addition of a small molecule.
A) I), II) and III)
B) I), and II)
C) II), III) and IV)
D) III), IV) and V)
E) II), IV) and V)
50) The physical properties of polymers depend on:
I) the average molecular mass of a chain
II) the strength of intermolecular forces between the chains
III) the reaction temperature applied during synthesis
IV) the degree of crystallinity
V) the reaction pressure
A) I), II), and IV)
B) II), III), and IV)
C) I), II), and V)
D) III), IV), and V)
E) II), IV), and V)
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51) Classify the following polymers as atactic, isotactic or syndiotactic:
A) Polymer A is isotactic, polymer B is atactic and polymer C is syndiotactic.
B) Polymer A is atactic, polymer B is isotactic and polymer C is syndiotactic.
C) Polymers A and B are isotactic and polymer C is syndiotactic.
D) Polymer A is isotactic and polymers B and C is syndiotactic.
E) Polymer A is syndiotactic, polymer B is isotactic and polymer C is atactic.
52) Which type of polymerization and which monomer(s) would you use to prepare poly(1,4-
phenylenediformamide) with the following structure?
A)
with chain reaction polymerization
B)
with condensation polymerization
C)
with chain reaction polymerization
D)
with step-reaction polymerization
E)
with chain reaction polymerization
53) Suggest possible compounds for A and B in the following scheme:
CH3CH2I + A → CH3CH2SH + B
A) A is HS– and B is I–
B) A is H2S and B is I2
C) A is H2S and B is HI
D) A is S2- and B is I–
E) A is H2S and B is I–
54) Suggest possible compounds for A, B and C in the following scheme:
A) A is Cl2, B is AlCl3 and C is meta chloronitrobenzene
B) A is Cl2, B is FeCl3 and C is ortho chloronitrobenzene
C) A is Cl2, B is FeBr3 and C is meta chloronitrobenzene
D) A is HCl, B is AlCl3 and C is para chloronitrobenzene
E) A is Cl2, B is AlBr3 and C is meta chloronitrobenzene
55) What is “retrosynthesis“?
A) a chemical analysis followed by chemical synthesis
B) a chemical synthesis followed by chemical analysis
C) a synthetic procedure designed to check old synthetic procedure
D) a synthetic strategy that works from the desired compound towards starting materials
E) a synthetic strategy that works from the starting materials towards desired product
56) Which of the following are nucleophiles?
I. CH3COCH3 II. CH3Br III. CH3CH2C≡C–
A) I
B) II
C) III
D) I + II
E) I + III
57) Which of the following are electrophiles?
I. CH3CH2NH2 II. Br+ III. CH3OH
A) I
B) II
C) III
D) I + II
E) I + III
58) What is the rate law for the SN1 reactions (S is substrate and N is nucleophile)?
A) rate = k[S][N]
B) rate = k[S]
C) rate = k[N]
D) rate = k[S]2
E) rate = k[S][N]2