SparkNotes: Review of Organic Chemistry IV: Substitution and Elimination Review Test

1. The rate law shows:

(A) The equilibrium constant of the reaction

(B) The molecules present in the transition state of the rate-limiting step

(C) The stability of the transition state of the rate-limiting step

(D) Both the stability and molecules present in transition state of the rate-limiting step

2. Which of the following is the best leaving group?

(A) MeO^-

(B) EtO^-

(C) HOH

(D) CH₃CH₂CO₂^-

3. In the E2 reaction, which of the following donates into the C-LG antibond?

(A) The base/nucleophile

(B) The α-hydrogen bond

(C) The β-hydrogen antibond

(D) the antiperiplanar β-hydrogen bond

4. A S_N2 reaction will be fastest in which of the following solvents?

(A) HOH

(B) Acetone

(C) Benzene

(D) Ethanol

5. A S_N1 reaction proceeds with

(A) Retention of stereochemical configuration

(B) Inversion of stereochemical configuration

(C) Removal of antiperiplanar β-hydrogens

(D) None of the above

6. In order for a E2 reaction to take place, which of the following must be present?

(A) Nonpolar, aprotic solvent

(B) Antiperiplanar β-hydrogen

(C) α-hydrogen(s)

(D) A good nucleophile

7. Choose the most stable olefin

(A) A

(B) B

(C) C

(D) D

8. If S_N2 reactions occurred through frontside attack, there would be

(A) Inversion of stereochemical configuration at the α-carbon

(B) Retention of stereochemical configuration at the α-carbon

(C) Inversion of stereochemical configuration at the β-carbon

(D) Both retention and inversion of stereochemical configuration at the β-carbon

9. Predict the product

(A)

(B)

(C)

(D) No reaction

10. Which of reaction mechanism will dominated for this reaction?

(A) S_N2

(B) E2

(C) S_N1

(D) E1

11.

X + Y → Z

The rate law of the above reaction is:

rate = k [X]² [Y]¹

What is the overall order of this rate law?

(A) 1

(B) 2

(C) 3

(D) 4

12. The E2 mechanism is

(A) Concerted

(B) Nonconcerted

(C) Two step

(D) Saytzeff

13. Why will this molecule not undergo an E2 elimination?

(A) The molecule has a poor leaving group

(B) The bulky side chains hinder base attack

(C) The molecule has no β-hydrogens

(D) The molecule has non-antiperiplanar α-hydrogens

14. A polar, aprotic solvent favors which mechanism most?

(A) S_N2

(B) E2

(C) S_N1

(D) E1

15. What is the rate-limiting step of the E1 mechanism?

(A) Quenching of the carbocation

(B) Formation of the carbocation

(C) elimination of the /beta-hydrogen

(D) Deprotonation of the solvent

16. Which of the following is a polar, aprotic solvent?

(A)

(B)

(C) Ethanol

(D) Benzene

17. What is the predominant E2 product?

(A)

(B)

(C)

(D)

18. Which of the following is the best description of the E2 reaction?

(A) Concerted bimolecular substitution

(B) Concerted bimolecular elimination

(C) Non-concerted bimolecular substitution

(D) Non-concerted bimolecular elimination

19. S_N2 reactions generally proceed with

(A) Retention of stereochemical configuration

(B) Inversion of stereochemical configuration

(C) Retention and inversion of stereochemical configuration

(D) β-elimination

20. What is the major elimination product of this reaction?

(A)

(B)

(C)

(D)

21.

What is the most reasonable reaction mechanism?

(A) S_N2

(B) E2

(C) S_N1

(D) E1

22.

Can this molecule undergo an E2 reaction?

(A) Yes

(B) No, there are no β-hydrogens

(C) No, the α-hydrogens are protected

(D) No, there are no antiperiplanar β-hydrogens

23. S_N2 reactions are favored by

(A) A strong base

(B) A good nucleophile

(C) Increased branching

(D) All of the above

24. Which one of the following bases is best suited for the E2 reaction?

(A) EtO^-

(B)

(C)

(D) EtOH

25.

Choose the most energetically stable E2 product.

(A)

(B)

(C)

(D)

26. An increase in a transition state's energy necessarily requires

(A) An increase in the rate of the reaction

(B) An increase in the rate of that particular step of the reaction

(C) A decrease in the rate of the reaction

(D) A decrease in the rate of that particular step of the reaction

27.

What will be the absolute stereochemistry of the product?

(A) S

(B) R

(C) A mixture of S and R

(D) No reaction

28. After elimination, which of the following will form the most stable alkene?

(A)

(B)

(C)

(D)

29.

How many β-hydrogens are there on this molecule?

(A) 0

(B) 1

(C) 2

(D) 3

30. How many of these β-hydrogens are antiperiplanar to the C-LG bond?

(A) 0

(B) 1

(C) 2

(D) 3

31. Predict the E2 elimination product.

(A)

(B)

(C)

(D)

32. Choose the most stable carbocation

(A)

(B)

(C)

(D)

33.

Predict the most stable carbocation intermediate formed after LG leaves.

(A)

(B)

(C)

(D)

34. Predict the product

(A)

(B)

(C)

(D)

35. All other things being equal, a S_N1 reaction will be fastest in which solvent?

(A) Benzene

(B) CCl₄

(C) Formadide (HCONH₂)

(D) Acetone

36.

This molecule does not undergo S_N2 attack. Choose the best explanation.

(A) Tosylate ion is a poor leaving group

(B) The path to the σ^* C-OTs antibond is blocked

(C) Ethoxide is a poor nucleophile

(D) The molecule lacks properly oriented β-hydrogens

37.

Molecule A is formed through a S_N2 reaction. Which pair of reactants would give the highest yield of molecule A?

(A) (CH₃)₃CBr and CH₃CH₂CH₂CH₂O^-

(B) (CH₃)₃CO^- and CH₃CH₂CH₂CH₂Br

(C) S_N1 not possible

(D) None of the above

38. The activation energy of concerted reaction A is twice that of concerted reaction B. Which of the following must be true?

(A) The rate constant of B is greater than the rate of A

(B) The rate constant of A is greater than the rate of B

(C) The product of A is more stable than the product of B

(D) The product of B is more stable than the product of A

39.

Why is this molecule not a good candidate for E1?

(A) It has no β-hydrogens

(B) The β-carbon is not secondary or tertiary

(C) The α-carbon is primary. The carbocation intermediate is too unstable for E1.

(D) The β-carbon is inaccessible

40. Which of the following is the best nucleophile?

(A) I^-

(B) Cl^-

(C) F^-

(D) EtO^-

41. Which of the following is the best leaving group?

(A) -I

(B) -OEt

(C) -OMe

(D) -O(t-Bu)

42. Which of the following will promote the fastest E1/S_N1 reaction?

(A)

(B)

(C)

(D)

43. Assuming no rotation about the C-C bond, which of the following pairs is antiperiplanar?

(A) A and F

(B) C and F

(C) B and D

(D) D and C

44. Choose the polar, protic solvent

(A) Acetone

(B) Formic acid (HCOOH)

(C)

THF

(D) Benzene

45.

Choose the most abundant E2 product

(A)

(B)

(C)

(D) No E2 reaction

46.

Predict the stereochemistry of the E2 product. (Hint: try rotating the C-C bond)

(A) trans

(B) cis

(C) Stereochemistry is indeterminate

(D) No E2 reaction

47. If the previous molecule is subjected to E1 conditions, what will be the stereochemistry of the most energetically stable product?

(A) trans

(B) cis

(C) Stereochemistry of most stable product is indeterminate

(D) No E1 reaction

48.

This molecule could be the product of only

(A) An E2 reaction

(B) An E1 reaction

(C) Both an E2 and an E1

(D) Neither an E2 or an E1

49.

X is thought to substitute for Br with a frontside attack mechanism. Predict the probably absolute stereochemistry of the product. Assume that X has the same CIP priority as Br.

(A) S

(B) R

(C) The product is achiral

(D) Stereochemistry is indeterminate for substitution reactions

50.

Predict the major S_N2 product.

(A)

(B)

(C)

(D) No S_N2 reaction

Review of Acids and Bases

Substitution and Elimination Review Test