12. Which of the following reactions provides anisole (PhOCH3) in a high yield?
a. phenol + sodium methoxide
b. bromobenzene + bromomethane
c. sodium phenoxide (PhONa) + bromomethane
d. bromobenzene + sodium methoxide
ANS: C
13. Which of the following reactions provides tert-butyl methyl ether in a high yield?
a. potassium tert-butoxide + iodomethane
b. sodium methoxide + tert-butyl bromide
c. methanol + tert-butyl alcohol in the presence of KOH
d. iodomethane + tert-butyl bromide in the presence of KOH
ANS: A
14. Which of the following ethers cannot be prepared by a Williamson ether synthesis?
a. tert-butyl phenyl ether
b. isopropyl methyl ether
c. anisole
d. tert-butyl methyl ether
ANS: A
18. What type of reactive intermediate is formed in the reaction of tert-butyl methyl ether with HBr to give tert-butyl bromide?
a. tert-butyl anion
b. tert-butoxide
c. tert-butyl radical
d. tert-butyl cation
ANS: D
19. What type of mechanism accounts for the cleavage of dibutyl ether upon treatment with HBr to give two moles of 1-bromobutane?
a. SN1
b. SN2
c. E1
d. E2
ANS: B
20. What type of mechanism accounts for the cleavage of tert-butyl methyl ether upon treatment with HBr?
a. SN1
b. SN2
c. E1
d. E2
ANS: A
21. What are the major products obtained upon treatment of anisole, PhOCH3, with excess HBr?
a. phenol and methanol
b. bromobenzene and bromomethane
c. phenol and bromomethane
d. bromobenzene and methanol
ANS: C
22. What are the major products obtained upon treatment of tert-butyl methyl ether with excess HBr?
a. tert-butyl alcohol and methanol
b. tert-butyl bromide and methanol
c. tert-butyl alcohol and bromomethane
d. tert-butyl bromide and bromomethane
ANS: D
23. What type of reactive intermediate is formed in the reaction of methyl propene with methanol in the presence of an acid catalyst to give methyl tert-butyl ether (MTBE)?
a. tert-butyl cation
b. tert-butyl radical
c. tert-butyl anion
d. tert-butoxide
ANS: A
47. Which of the following ions forms the strongest complex with 18-crown-6?
a. Li+
b. Na+
c. K+
d. Rb+
ANS: C
48. Which of the following statements is not true?
a. Crown ethers complex alkali metal ions by donation of lone pairs from the oxygen atoms to the metal cation.
b. Metal ion complexes of crown ethers dissolve in nonpolar aprotic organic solvents
c. Addition of 18-crown-6 to a solution of benzyl bromide and potassium cyanide in a nonpolar solvent increases the rate of nucleophilic substitution.
d. 18-Crown-6 is a planar molecule
ANS: D
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