25. What is the best reagent for the following reaction? Ph OH OH Ph OH ?  
(A) PCC
(B) Na₂Cr₂O₇, H₂SO₄
(C) DMSO, (COCl)₂ then Et₃N
(D) MnO₂
(E) H2CrO4

21. What reagent should be used for the following reaction? ?   (A) CH3CH2MgBr (B) CH3CH2Li (C) (CH3CH2)2Zn (D) CH3CH2B(OH)2 (E) (CH3CH2)2CuLi

22. Which of the following alkenes is most reactive toward ozonolysis? 

23. Which of the following ketones show strong characteristic band at 1815 cm-1?

24. In aromatic nitration reactions, nitric acid (HNO3) is used in conjunction with the stronger acid, sulfuric acid, H2SO4, to form an intermediate. Which of the following could be the formula for this intermediate? (A) NO3(B) H3SO4 (C) H2NO3(D) HNO2 (E) NO

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

27. What product would be obtained by the following reaction?(A)(B)(C)(D)(E) None of the above.

28. Which fragment would you expect to be the base peak in the mass spectrum of limonene?  (A) m/z = 136 (B) m/z = 121 (C) m/z = 93 (D) m/z = 68 (E) m/z = 49

29. What is the major product of the following reaction? ? 

30. Which of the following would correctly describe the respective 13C NMR and 1 H NMR spectra for the indicated atoms for the compound shown below?  (A) Atom 1 would produce a peak at 205 ppm and atom 2 would appear as doublet (B) Atom 1 would produce a peak at 175 ppm and atom 2 would appear as a singlet (C) Atom 1 would produce a peak at 205 ppm and atom 2 would appear as a triplet (D) Atom 1 would produce a peak at 175 ppm and atom 2 would appear as a triplet (E) Atom 1 would produce a peak at 175 ppm and atom 2 would appear as a doublet

31. What is the major product of the following reaction?