23. Which sequence ranks the following aromatic rings of this compound in order of increasing reactivity in an electrophilic aromatic substitution reaction (slowest to fastest reacting)? 
(A) 3 < 2 < 1
(B) 2 < 3 < 1
(C) 2 < 1 < 3
(D) 1 < 3 < 2
(E) 1 < 2 < 3

19. The regioselectivity and stereospecificity in the oxymercuration-demercuration of an alkene is best described as: (A) Markovnikov orientation with syn-addition (B) Markovnikov orientation with anti-addition (C) anti-Markovnikov orientation with syn-addition (D) anti-Markovnikov orientation with anti-addition (E)Markonikov orientation with both syn- and anti-addition

20. What is the major product of the following reaction?(A)(B)(C)(D)(E) None of the above.

21. What is the major product of the following reaction?  (A) I (B) II (C) III (D) IV (E) V

22. Which of the following descriptions of the nucleoside uridine does NOT apply to the structure of the molecule? (A) The uracil base is directly bonded to the 1' position of ribofuranose in the α position. (B) The ribofuranose moiety is found in only the D configuration. (C) Nitrogen, at position 1 in the uracil base, is directly bonded to the ribofuranose moiety. (D) The 5' OH group is replaced with phosphate(s) in the nucleotide structure. (E) None of the above

24. Which sequence ranks the indicated protons in order of increasing acidity?  (A) 3 < 2 < 1 (B) 2 < 3 < 1 (C) 2 < 1 < 3 (D) 1 < 3 < 2 (E) 1 < 2 < 3

25. Which pair of structures represents the same compound? (A) I and II (B) II and IV (C) III and IV (D) III and V (E) IV and V

26. What is the major product of the following reaction?  (A) I (B) II (C) III (D) IV (E) V

27. What is the major product of the following reaction? (A) I (B) II (C) III (D) IV (E) V

28. Which of the following is the strongest nucleophile? (A) NaOH (B) NaOMe (C) KOH (D) KOMe (E) KSMe

【已刪除】複選題29. Which would be the major product of the reaction shown? (A) I (B) II (C) III (D) IV (E) V (AB)送分