Reviewquestions_21

Reviewquestions_21 - 1) Which of the following is the most...

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1 1) Which of the following is the most reactive carboxylic acid derivative? A) ester B) anhydride C) nitrile D) acid chloride E) amide Answer: D Diff: 1 2) N -Methylacetamide is an example of: A) a primary amide B) a secondary amide C) a tertiary amide D) an N, N -disubstituted amide E) an imine Answer: B Diff: 1 3) Which of the following are strongly hydrogen bonded in the liquid phase? A) nitriles B) esters C) secondary amides D) tertiary amides E) acid chlorides Answer: C Diff: 2 9) In nucleophilic acyl substitution, : A) protonation of the carbonyl is followed immediately by loss of the leaving group. B) loss of the leaving group is followed by rearrangement of the carbocation. C) addition to the carbonyl by a nucleophile is followed by loss of the leaving group. D) ester hydrolysis is followed by deprotonation. E) an S N 2 reaction occurs. Answer: C Diff: 2 10) A correct order of reactivity of acid derivatives towards nucleophilic attack is: A) esters > acid anhydrides > amides. B) anhydrides > amides > esters. C) carboxylates > esters > amides. D) anhydrides > acids > acid chlorides. E) anhydrides > amides > carboxylates. Answer: E Diff: 1
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2 11) Using the two key resonance structures for an ester, show how resonance stabilization is lost when an ester is attacked by a nucleophile. Answer: Diff: 3 12) Provide a detailed, stepwise mechanism for the reaction of propanoyl chloride with ammonia. Answer: Diff: 2 13) Provide a detailed, stepwise mechanism for the reaction of propanoic anhydride with phenol. Answer: Diff: 2 14) Using potential energy diagrams, explain why alkoxides act as leaving groups in nucleophilic acyl substitutions but not in S N 2 reactions. Answer: See Figure 21-10, p.963
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Reviewquestions_21 - 1) Which of the following is the most...

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