CHEMISTRY
Keghan
Chapter 8
MULTIPLE CHOICE QUESTIONS
Topic: Structure Elucidation
1. An alkene adds hydrogen in the presence of a catalyst to give 3,4-dimethylhexane.
Ozonolysis of the alkene followed by treatment with zinc and acetic acid gives a single organic product. The structure of the alkene is:
CH3
A)
CH3CH=C-CHCH2CH3
(cis or trans)
CH3
CH3
B)
CH3CH2C=CCH3
(cis or trans)
CH2CH3
C)
CH3
CH2=CCH2CHCH2CH3
CH3
CH2
D)
CH3CH2CCHCH2CH3
CH3
CH3
E)
CH3CH2CHCHCH=CH2
CH3
Ans: B
241
Keghan
Chapter 8
Topic: Structure Elucidation
2. Ozonolysis of compound Z yields the products shown below. What is the structure of Z?
O
Z
1) O3
2) Zn, HOAc
O
2HCH + CH3CCH2CH
O
I
II
III
O
H
IV
A)
B)
C)
D)
E)
O
V
I
II
III
IV
V
Ans: B
242
Keghan
Chapter 8
Topic: Structure Elucidation
3. Compound C has the molecular formula C7H12. On catalytic hydrogenation, 1 mol of C absorbs 1 mol of hydrogen and yields a compound with the molecular formula C7H14.
On ozonolysis and subsequent treatment with zinc and acetic acid, C yields only:
O
O
The structure of C is:
I
II
IV
A)
B)
C)
D)
E)
III
V
I
II
III
IV
V
Ans: E
Topic: Structure Elucidation
4. Compound X has the molecular formula C6H10. X decolorizes bromine in carbon tetrachloride. X also shows IR absorption at about 3300 cm-1. When treated with excess hydrogen and a nickel catalyst, X yields 2-methylpentane. The most likely structure for X is:
A)
B)
C)
D)
E)
Ans: D
243
Keghan
Chapter 8
Topic: Structure Elucidation
5. An unknown compound, A, has the molecular formula C7H12. On oxidation with hot aqueous potassium permanganate, A yields CH3CH2COOH and (CH3)2CHCOOH.
Which of the following structures best represents A?
A)
B)
C)
D)
E)
Ans: C
244
Keghan
Chapter 8
Topic: Structure Elucidation
6. Determine a possible structure for an alkene, X, formula
Chapter 8
MULTIPLE CHOICE QUESTIONS
Topic: Structure Elucidation
1. An alkene adds hydrogen in the presence of a catalyst to give 3,4-dimethylhexane.
Ozonolysis of the alkene followed by treatment with zinc and acetic acid gives a single organic product. The structure of the alkene is:
CH3
A)
CH3CH=C-CHCH2CH3
(cis or trans)
CH3
CH3
B)
CH3CH2C=CCH3
(cis or trans)
CH2CH3
C)
CH3
CH2=CCH2CHCH2CH3
CH3
CH2
D)
CH3CH2CCHCH2CH3
CH3
CH3
E)
CH3CH2CHCHCH=CH2
CH3
Ans: B
241
Keghan
Chapter 8
Topic: Structure Elucidation
2. Ozonolysis of compound Z yields the products shown below. What is the structure of Z?
O
Z
1) O3
2) Zn, HOAc
O
2HCH + CH3CCH2CH
O
I
II
III
O
H
IV
A)
B)
C)
D)
E)
O
V
I
II
III
IV
V
Ans: B
242
Keghan
Chapter 8
Topic: Structure Elucidation
3. Compound C has the molecular formula C7H12. On catalytic hydrogenation, 1 mol of C absorbs 1 mol of hydrogen and yields a compound with the molecular formula C7H14.
On ozonolysis and subsequent treatment with zinc and acetic acid, C yields only:
O
O
The structure of C is:
I
II
IV
A)
B)
C)
D)
E)
III
V
I
II
III
IV
V
Ans: E
Topic: Structure Elucidation
4. Compound X has the molecular formula C6H10. X decolorizes bromine in carbon tetrachloride. X also shows IR absorption at about 3300 cm-1. When treated with excess hydrogen and a nickel catalyst, X yields 2-methylpentane. The most likely structure for X is:
A)
B)
C)
D)
E)
Ans: D
243
Keghan
Chapter 8
Topic: Structure Elucidation
5. An unknown compound, A, has the molecular formula C7H12. On oxidation with hot aqueous potassium permanganate, A yields CH3CH2COOH and (CH3)2CHCOOH.
Which of the following structures best represents A?
A)
B)
C)
D)
E)
Ans: C
244
Keghan
Chapter 8
Topic: Structure Elucidation
6. Determine a possible structure for an alkene, X, formula