Practice Second Examination
Chem 241
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Due: October 14, 2013
Section
Credit
Part 1
50
Part 2
14
Part 3
36
Total
100
Score
1
Part 1. Multiple choice – Please select the answer that is most correct for each problem. Place
the letter corresponding to the correct answer in each box (2 points each).
1. The most stable carbocation of the following is
(A)
(B)
(C)
2.
(D)
(E)
The following molecule is
(A) R
(B) S
(C) Not Chiral
(D) R and S
(E) none of these
3.
What is the molecular formula of the hydrocarbon that contains 5 carbon atoms, one ring,
and one π bond?
(A) C5H6
(B) C5H8
(C) C5H10
(D) C5H12
4.
(E) none of these
Which of the following statements about ethene, C2H4, is incorrect?
(A) The H-C-H bond angles are approximately 109.5°.
(B) All of the hydrogen atoms are in the same plane.
(C) There is a total of five sigma bonds.
(D) The carbon atoms are sp2 hybridized.
(E) All above are correct
5. Which of the following isomers of C7H14 contain the most stable double bond.
(A) 1
(B) 2
(C) 3
(D) 4
2
(E) 1 & 3
6. The IUPAC name for the following molecule is:
(A) 1-ethyl-3-methyl-2-cyclohexene
(B) 3-ethyl-1-methyl-1-cyclohexene
(C) 1-ethyl-3-methyl-2-cyclopentene
(D) 3-ethyl-1-methyl-1-cyclopentene
(E) cyclohedgeballene
7. The IUPAC name for the following molecule is:
(A) (Z)-3-bromo-6-ethyl-1,3-octadiene
(B) (E)-3-bromo-6-ethyl-1,3-octadiene
(C) (Z)-6-bromo-3-ethyl-5,7-octadiene
(D) (E)-3-bromo-6-methyl-1,3-octadiene
(E) Not given
8. Markovnikov’s rule predicts the following product for the reaction below:
(A)
(B)
(C)
(D)
3
(E)
9. How many intermediates are present in the following reaction diagram?
(A) 3
(B) 4
(C) 5
(D) 2
(E) 1
10. Which of the following compounds will react most rapidly with HCl (Hint: the compound
that reacts the most rapidly can form the most stable carbocation)?
(A) 5-methyl-1-hexene
(B) 4-methyl-1-hexene
(C) (E)-5-methyl-2-hexene
(D) (E)-2-methyl-3-hexene
(E) 2-methyl-2-hexene
11. If you had to take 2 courses more to obtain a chemistry minor, you would …
(A) Definitely apply for the minor (B) would consider a minor (C) Need to think more
(D) Probably wouldn’t apply for a minor (E) Definitely wouldn’t apply for the minor
12. The addition of chlorine to cyclobutene gives:
(A) meso-1,3-dichlorocyclobutane
(B) cis-1,2-dichlorocyclobutane
(C) trans-1,2-dichlorocyclobutane
(D) cis-1,3-dichlorocyclobutane
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(E) none of these
13. In the first step of adding HBr to a double bond, the double bond attacks H to generate a:
(A) Carbanion intermediate
(B) Strong Base
(C) Good nucleophile
(D) A carbocation intermediate (E) password
14. The conversion of carbocation 1 to carbocation 2 is made possible by means of a
(A) hydronium shift
(D) carbocation shift
15.
(B) Lock Rearrangement
(C) hydride shift
(E) methyl shift
The major organic product generated in the reaction below is….
5
16.
Draw the major organic product generated in the reaction below.
17. The major organic product in the reaction below is acetic acid and which of the following:
6
18. Provide the proper IUPAC name for the alkene shown below.
(A) 1-bromo-2-methyl-2-cyclohexene
(B) 2-bromo-1-methyl-1-cyclohexene
(C) 2-bromo-1-methylcyclohexene
(D) 6-bromo-1-methylcyclohexene
(E) 1-bromo-6-methyl-6-cyclohexene
19. Which of the following is the best reaction sequence to use if one wants to accomplish an
Anti-Markovnikov addition to install an alcohol functional group?
(A) water + dilute sulfuric acid
(B) water + concentrated sulfuric acid
(C) oxymercuration – 1. Hg(OAc)2 2.NaBH4
(D) hydroboration- 1. BH3/THF 2. -OH, H2O2, H2O
(E) none of the above
20. Which of the products will be most abundant for the reaction given below:
7
21. Which of the statements is most true about the following molecule?
(A) It contains 2 assymetric centers and is not chiral
(B) It contains no assymetric centers and is not chiral
(C) It contains 2 assymetric centers and is chiral
(D) It contains no assymetric centers and is chiral
(E) It contains 4 assymetric centers and is not chiral
22. Which of the following reagents gives the reaction shown below?
CH3CH= CH2 + ? → CH3CH2CH3
(A) H2/HCl
(B) H2O /Br2
(C) H2/PtO2
(D) H2O/Ni
(E) H2O/H2SO4
23. Which of the following compounds has an asymmetric center?
(A) I
(B) II
(C) III
(D) IV
(E) V
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24. Choose the enantiomer of the compound below.
(A)
(B)
(C)
(D)
(E)
25. A molecule with a specific rotation of 0 o can be:
a)
b)
c)
d)
e)
Racemic
Enantiomerically pure
Not chiral
a and b
a and c
9
conformational
diastereomers
enantiomers
Identical
II. Part 2. (14 points) – Indicate the type of stereochemical relationship that best applies to the
following pairs of compounds by checking the appropriate box (one only, 2 points each).
1.
2.
3.
4.
5.
6.
The configuration of C(3) of the leftmost structure of #4 is:
R
S
(circle one)
7.
The configuration of C(2) of the leftmost structure of #4 is:
R
S
(circle one)
10
Part 3. Short Answer:
Complete the following equations by drawing the structure of the product(s) of the reaction, or
the missing reactant in the boxes provided (36 points).
1. (6 points)
2. (3 points)
3. (4 points)
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4. (3 points)
5. (3 points)
6. (4 points)
7.
(3 points)
12
8.
Provide an arrow pushing mechanism for each of the following transformations (10 points
total).
a. (5 points)
b.
(5 points)
13
Extra sheet of paper
14
Extra Problems:
Give the IUPAC name for the following compound.
(A) isoprene
(B) 3-methyl-1,3-butadiene
(C) 2-methyl-1,3-butadiene
(D) 2-methyl-2,3-butadiene
(E) isobutadiene
The IUPAC name for the following molecule is:
(B) 5-methyl-2,4-heptene
(B) 5-methylhex-2,4-dien-1-ol
(C) 5-methylhept-2,4-dien-1-ol
(D) 2-methylhex-2,4-dien-6-ol
(E) Chicken Gumbo
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