21. Which of the following are correct Lewis structures, including formal charges, for nitric acid, HNO₃? 

 
(A) A only
(B) B only
(C) C only
(D) both B and C
(E) A, B, and C

17. How many distinct alkene products are possible when the alkyl iodide below undergoes E2 elimination?  (A) 1 (B) 2 (C) 3 (D) 4 (E) 5

18. Which of the following describes the compound below?  (A) bridged bicyclic (B) fused bicyclic (C) spiro bicyclic (D) bridged tricyclic (E) fused tricyclic

19. What method will produce the transformation?  (A) Li / ND3 (B) (sia)2BD then H2O (C) CH3CH2MgBr then D3O+ (D) (sia)2BD then D2O (E) LiAlD4 then D2O

20. Energy is __________ when bonds are formed and is __________ when bonds are broken; therefore, bond dissociation energies are always __________. (A) released / consumed / exothermic (B) released / consumed / endothermic (C) consumed / released / exothermic (D) consumed / released / endothermic (E) consumed / released / isothermic

22. Which of the following alkyl chlorides is least likely to undergo rearrangement during a solvolysis reaction? (A) cis-1-chloro-2-ethylcyclohexane (B) trans-1-chloro-2-ethylcyclohexane (C) 2-chloro-4-methylpentane (D) 2-chloro-3-methylpentane (E) 2-chloro-2-methylpentane

23. 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 of the following is correct in order of decreasing nucleophilicity toward methyl iodide in methanol? (A) CH3O- > CH3S- > CN- > Br- (B) CH3O- > CN- > CH3S- > Br- (C) CN- > CH3O- > CH3S- > Br- (D) CH3S- > Br- > CH3O- > CN- (E) CH3S- > CN- > CH3O- > Br-

25. Which of the following compounds will undergo SN2 reaction most readily? (A) (CH3)3CCH2I (B) (CH3)3CCl (C) (CH3)2CHI (D) (CH3)2CHCH2CH2CH2I (E) (CH3)2CHCH2CH2CH2Cl

26. Which of the following carbonyl compounds can be reduced by H2/Raney Ni? (A) acetic acid (B) ethyl acetate (C) acetyl chloride (D) acetamide (E) N-methyl acetamide

27. Which of the following is the rate-determining step for the monobromination of cyclohexane? (A) Step I (B) Step II (C) Step III (D) Step IV (E) Step V