CHEMISTRY

5345 Words Nov 12th, 2013 22 Pages
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
…show more content…
A)
B)
C)
D)
E)

i. O3 ii. Zn, HOAc

H
O

+

4-Hexen-1-yne
3-methyl-1-hexene
(E)-2-hexene
(Z)-2-hexene
4-methyl-1-hexene
Ans: E r 247

H

O

Keghan
Chapter 8

Topic: Structure Elucidation
12. Which alkene would yield only CH3CH2COOH on oxidation with hot alkaline potassium permanganate (followed by acid work-up)?
A) (E)-2-hexene
B) (Z)-2-hexene
C) 2-methyl-2-pentene
D) (E)-3-hexene
E) (E)-4-methyl-2-pentene
Ans: D
Topic: Structure Elucidation
13. An unknown compound, B, has the molecular formula C7H12. On catalytic hydrogenation 1 mol of B absorbs 2 mol of hydrogen and yields 2-methylhexane. B has significant IR absorption band at about 3300 and 2200 cm-1. Which compound best represents B?
A) 3-methyl-1-hexyne
B) 5-methyl-2-hexyne
C) 5-methyl-1,3-hexadiene
D) 5-methyl-1-hexyne
E) 2-methyl-1,5-hexadiene
Ans: D
Topic: Structure Elucidation
14. What compound would yield an equimolar mixture of CH3CH2CH2CHO and CH3CHO upon treatment with O3, followed by Zn/HOAc?
A) 1-Hexene
B) cis-2-Hexene
C) trans-2-Hexene
D) More than one of these
E) None of these
Ans: D
Topic: Structure Elucidation
15. An alkene with the molecular formula C8H16 undergoes ozonolysis to yield a mixture of
(CH3)2C=O and (CH3)3CCHO. The alkene is:
A) 2,2-Dimethyl-2-hexene
B) 2,3-Dimethyl-2-hexene
C) 2,4-Dimethyl-2-hexene
D) 2,4,4-Trimethyl-2-pentene
E) More than one of the above is a possible answer.
Ans: D

248

Keghan
Chapter 8
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