CHM 234, Spring 2015
QUIZ #10 ANSWER KEY
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QUESTION 1
MC32n
For the following reactions indicated as 1, 2 and 3,
which is the correct order of INCREASING rate of
electrophilic aromatic substitution?
O
N
O
NO2
1
NH2
2
Cl
3
Cl2
AlCl3
this is STRONG WITHDRAWING group due to
the formal positive charge on the nitrogen
in the nitro group, so is DEACTIVATING,
and decreases the reaction rate
this is a STRONG DONATING group on a πsystem, due to the resonance effect of
Cl2
the non-bonding electrons on the
nitrogenm,
thus is ACTIVATING, and
AlCl3
increases the rate of the reaction
this is WEAK WITHDRAWING group, even
though the Cl has non-bonding electrons
Cl2
it is so electronegative that the
inductive
effect outweighs the weak
AlCl3
resonance donation effect, Cl is thus
DEACTIVATING and decreases the reaction
rate somewhat
A 1 (slowest) < 2 < 3 (fastest)
B 2 (slowest) < 3 < 1 (fastest)
C 1 (slowest) < 3 < 2 (fastest)
D 3 (slowest) < 2 < 1 (fastest)
QUESTION 2
MC32o
give the product of the following electrophilic
aromatic substitution reaction
CN
HNO3/H2SO4
NO2
CN
CN
O2N
CN
O2N
A
B
C
Do not give the answer D
meta-position
+
C
N
=
CN
HNO3/H2SO4
electron withdrawing due
to dipolar nature of the
carbon-nitrogen triple
bond, thus META-directing
O2N
CN
QUESTION 3
MC32l
Which of the following structures would undergo
electrophilic aromatic substitution fastest?
Me
O
O
N
H
Me
B
A
O
N
H
OMe
O
N
H
N
H
MeO
C
D
donating groups are ACTIVATING, they make electrophilic
aromatic substitution reactions FASTER, the stronger the
donating group, the faster the reaction
O
weak
donating
N moderate
H withdrawing
#1
Me
O
B
N
moderate
H withdrawing
#1
O
strong
donating #1
MeO
O
N
moderate
H withdrawing
O
D
#2
N
moderate
H donating
MeO
OMe
moderate
donating
O
C
Me weak
donating
#2
N
H
N moderate
H withdrawing
#2
N
moderate
H donating
Me
Me
O
#1
O
A
#2
OMe strong
donating
N
moderate
H donating
the #2 ring in structure D has both moderate and a strong
donating groups, THIS ring on THIS structure is the most
activated, reaction would be fastest HERE
QUESTION 4
QUESTION 5
QUESTION 6
QUESTION 7
QUESTION 8