大二上学期有机化学题库ch08'

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:

A)

B)

C)

D)

E)

Ans

B:

2.

What is the structure of the compound Z that yields 2 mol of formaldehyde

and 1 mol of upon ozonolysis followed by treatment with zinc in acetic acid?

A) I

B) II

C) III

D) IV

E) V

Ans:

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:

The structure of C is:

A) I

B) II

C) III

D) IV

E) V

Ans:

E

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

5. An unknown compound, A, has the molecular formula C7H12. On oxidation with hot

aqueous potassium permanganate, A yields CH3CH2COOH and .

Which of the following structures best represents A?

A)

B)

C)

D)

E)

Ans:

C

6. An alkene, X, with the formula C7H10 adds one mole of hydrogen on catalytic

hydrogenation. On treatment with hot basic KMnO4 followed by acidification, X yields

Which is a possible structure for X?

A) I

B) II

C) III

D) IV

E) None of these

Ans:

A

7. An optically active compound, Y, with the molecular formula C7H12 gives a positive test

with cold dilute KMnO4 and shows IR absorption at about 3300 cm-1. On catalytic hydrogenation, Y yields Z(C7H16) and Z is also optically active. Which is a possible structure for Y?

A) CH3CH2CH2CH2CH2C CH

B)

C)

D)

E)

Ans:

B

8. One mole of an optically active compound, X, with the molecular formula C6H8 reacts

with three moles of hydrogen in the presence of a catalyst to yield an optically inactive product that cannot be resolved. X also exhibits IR absorption at approximately 3300 cm-1. Which is a possible structure for X?

A)

B)

C)

D)

E)

Ans:

E

9. An alkene with the molecular formula C8H14 is treated with ozone and then with zinc

and acetic acid. The product isolated from these reactions is

What is the structure of the alkene?

A) I

B) II

C) III

D) IV

E) V

Ans

C:

10. An optically active compound, A, with the molecular formula C7H12 reacts with cold

dilute KMnO4 and gives IR absorption at about 3300 cm-1. On catalytic hydrogenation,

A is converted to

B (C7H16) and B is also optically active. Which is a possible

structure for A?

A) I

B) II

C) III

D) IV

E) V

Ans:

E

11. Which alkene would undergo the following reaction?

A)

B)

C)

D)

E)

Ans:

E

12. Which alkene would yield only CH3CH2COOH on oxidation with hot alkaline

potassium permanganate?

A)

B)

C)

D)

E)

Ans:

D

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 an IR absorption band at about 3300 cm-1. Which compound best represents B?

A)

B)

C)

D)

E)

Ans:

D

14.

What compound would yield 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

15. An alkene with the molecular formula C8H16 undergoes ozonolysis

to yield and . 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

16. Which of the following would be soluble in cold concentrated sulfuric acid, decolorize

bromine in carbon tetrachloride, and exhibit IR absorption at about 3300 cm-1?

A) CH3CH=CHCH3

B) CH3CH=CH2

C) CH3CH2C≡CH

D) CH3CH2CH2CH3

E) All of these would give positive results in each test.

Ans:

C

17. Which of these compounds will react with each of these reagents?

cold concd. H2SO4

Br2 in CCl4

A) CH3CH2CH=CHCH3

B) CH3CH2CH2CH=CH2

C) CH3CH2C≡CCH3

D) (CH3)2CHC≡CH

E) All of these

Ans:

E

18. Which of the following reagents might serve as the basis for a simple chemical test that

would distinguish between pure 1-hexene and pure hexane?

A) Bromine in carbon tetrachloride

B) Dilute aqueous potassium permanganate

C) Concentrated sulfuric acid

D) All of the above

E) Answers A) and B) only

Ans:

D

19. Which reagent or test could be used to distinguish between 2-pentyne and 1-pentyne?

A) Br2/CCl4

B) IR examination

C) Concd. H2SO4

D) KMnO4,OH-

E) None of these

Ans:

B

20. Which reagent or test could be used to distinguish between 1-bromohexane and hexane?

A) Br2/CCl4

B) IR examination

C) dilute KMnO4

D) cold concd. H2SO4

E) None of these

Ans:

B

21. Which of the following could be used to distinguish between 1-octyne and 2-octyne?

A) Treatment with 2 mol of HX

B) Addition of water

C) Reaction with KMnO4

D) Decolorization of bromine in CCl4

E) IR examination

Ans

E:

22. A reagent or test that could be to distinguish between 1-pentene and 1-pentyne would

be:

A) Bromine in carbon tetrachloride

B) Dilute aqueous potassium permanganate

C) CrO3 in H2SO4

D) H2SO4

E) IR examination

Ans:

E

23. Which of the following could be used as the basis for a simple test that would

distinguish between 1-pentyne and pentane?

A) IR examination

B) Br2/CCl4

C) KMnO4/H2O

D) Two of these

E) All of these

Ans:

E

24. Which reagent or test could be used to distinguish between cyclopentane and

cyclopentene?

A) Br2/CCl4

B) AgNO3/EtOH

C) concd H2SO4

D) More than one of the above

E) None of the above

Ans:

D

25. What would be the major product of the following reaction?

A) I

B) II

C) III

D) IV

E) V

Ans:

B

26. Treating 1-methylcyclohexene with HCl would yield primarily which of these?

A) I

B) II

C) III

D) IV

E) V

Ans:

C

27. Which product would you expect from the acid-catalyzed addition of water to

A) I

B) II

C) III

D) IV

E) V

Ans

D:

28. The addition of bromine to cyclohexene would produce the compound(s) represented by

structure(s):

A) I alone

B) II alone

C) II and III

D) III alone

E) I and II

Ans:

C

29. What product would you expect from addition of deuterium chloride to

2-cyclohexyl-4-methyl-2-pentene?

A) I

B) II

C) III

D) IV

E) V

Ans:

C

30. What is the chief product of the reaction of IBr with 1-butene?

A)

B)

C)

D)

E)

Ans:

A

31. What is the chief product of the acid-catalyzed hydration of 2-methyl-2-butene?

A)

B)

C)

D)

E)

Ans:

C

32. What product would result from the following reaction?

A) I

B) II

C) III

D) IV

E) V

Ans:

C

33. Acid-catalyzed hydration of 2-methyl-1-butene would yield which of the following?

A)

B)

C)

D)

E)

Ans:

B

34. Which of these is not formed when cyclopentene reacts with an aqueous solution of

bromine?

A) I

B) II

C) III

D) IV

E) V

Ans:

E

35. What would be the major product of the following reaction?

A) I

B) II

C) III

D) IV

E) V

Ans:

A