Organic Chemistry Problems Chapter 15 Answer Key

Practice problems chapter 15 1) Which of the following structures contribute(s) to the resonance hybrid of the intermediate formed when acetanilide undergoes para-bromination? a) I b) II c) III d) IV e) All of these choices. Answer: E 2) Which of the following contributors to the resonance stabilized hybrid formed when aniline undergoes para-chlorination would be exceptionally stable? +NH2 : NH2 : NH 2 : NH 2 + + + H Cl H Cl H Cl H Cl I II III IV a) I b) II c) III d) IV e) None of these choices. Answer: B 3) Which of these liquids would be unsuitable as an inert solvent for a Friedel-Crafts reaction? a) Chlorobenzene b) Nitrobenzene c) Acetophenone d) (Trifluoromethyl) benzene e) All of these choices could be used. Answer: A 4) This substituent deactivates the benzene ring towards electrophilic substitution but directs the incoming group chiefly to the ortho and para positions. a) -OCH2CH3 b) -NO2 c) -F d) -CF3 e) -NHCOCH3 Answer: C 5) This molecule does not normally participate as a reactant in a Friedel-Crafts reaction. a) Benzene b) Chlorobenzene c) Nitrobenzene d) Toluene e) tert-Butylbenzene Answer: C 6) What is the chief product of the Friedel-Crafts alkylation of benzene with 1-butene and HF? a) butylbenzene b) 2-phenylbutane c) 2-methyl-1-phenylpropane d) t-butylbenzene e) 2,2-diphenylbutane Answer: B 7) A mixture of chlorobenzene (1 mol) and anisole (1mol) is allowed to react with Br2 (0.5 mol) in the presence of trace amounts of FeBr3. What is the principal product of the competing reactions? a) 1-bromo-4-chlorobenzene b) 1-bromo-2-chlorobenzene c) 1-bromo-3-chlorobenzene d) 4-bromoanisole e) 3-bromoanisole Answer: D 8) Which of the following reactions could be used to synthesize tert-butylbenzene? a) b) c) d) All of these choices. e) None of these choices. Answer: D 9) Consider the following reaction: what is the expected product? NH2 Br2, H2 O ? Cl NH2 Br Br H2 N Cl Br I Cl Br Br Cl NH 2 II III NH 2 NH2 Br Br Br a) I b) II c) III d) IV e) V Answer: B Br Cl Cl IV V 10) Which of the following reactions would produce isopropylbenzene? Cl Benzene a) Benzene b) AlCl3 HF OH Benzene c) H 2SO4 Br Benzene AlCl3 d) e) All of these choices. Answer: E 11) Which of the following reactions would give the product(s) indicated in substantial amounts (i.e., in greater than 50% yield)? IV. None Ans D 12) The major product(s) of the following reaction, would be: a) I b) II c) III d) IV e) V Answer: E 13) What would be the product of the following reaction sequence? OH i) SOCl2 ? ii) C6 H6 , AlCl3 O iii) Zn(Hg), HCl, heat O O OH OH I II IV III V a) I b) II c) III d) IV e) V Answer: E 14) What would you expect to be the major product obtained from the following reaction? O HNO3 H2SO4, heat HN O ? O NO2 O HN HN O 2N HN O 2N II I O HN IV III O HN NO2 NO2 V a) I b) II c) III d) IV e) V Answer: E 15) The major product(s), A, of the following reaction, would be: a) I b) II c) A mixture of I and II. d) III e) IV Answer: E 16) What would you expect to be the major product obtained from the following reaction? a) I b) II c) III d) IV e) V Answer: E 17) Toluene is subjected to the action of the following reagents in the order given: (1) KMnO4,OH-, heat; then H3O+ (2) HNO3, H2SO4 (3) Br2, FeBr3 What is the final product of this sequence? a) I b) II c) III d) IV e) V Answer: A 18) What product would result from the following series of reactions, a) I b) II c) III d) IV e) V Answer: D 19) Arrange the following compounds in order of decreasing reactivity in electrophilic substitution: O I O II Br III NO2 IV a) V > II > I > III > IV b) II > V > III > I > IV c) IV > I > III > V > II d) III > II > I > IV > V e) IV > V > II > I > III Answer: B 20) Which of the following carbocations would be most stable? V a) b) c) d) e) Answer: E