54. The pinacol rearrangement proceeds via intermediate.
(A) carbanion
(B) carbocation
(C) radical
(D) carbene
(E) neutral

50. (S) (+)-Butanol shows a specific rotation at +13.52o . What is the ratio of (S) (+)-butanol and (R) (-)-butanol when the measured rotation equals to +6.76o ? (A) (S) : (R) = 4 : 1 (B) (S) : (R) = 2 : 1 (C) (S) : (R) = 1 : 2 (D) (S) : (R) = 1 : 2.5 (E) (S) : (R) = 3 : 1

51. Consider the SN1 reaction of tert-butyl chloride with iodide ion: (CH3)3C-Cl + I - → (CH3)3C-I + Cl- If the concentration of iodide ion is doubled, the rate of forming tert-butyl iodide will: (A) Double (B) Increase 4 times (C) Remain the same (D) Decrease (E) Triple

52. Which of the following functional groups would NOT show an IR absorbance above 3000 cm-1? (A) An amine (NH2) (B) A carbonyl (C=O) (C) An alcohol (OH) (D) A vinylic carbon-hydrogen bond (=C-H) (E) A methylene hydrogen (-CH2-)

53. Which part of the electromagnetic spectrum interacts with the nuclear spins of protons ? (A) Radio Waves (B) X-Ray radiation (C) Visible Light (D) Infrared radiation (E) Ultra violet light

55. Which carbon in the following sugar is the anomeric carbon atom? (A) a (B) b (C) c (D) d (E) e

56. A tree diagram for the splitting of a proton Ha is reproduced below. What is the origin of this splitting pattern? (A) Ha is coupled to two nonequivalent hydrogens with identical coupling constants. (B) Ha is coupled to two nonequivalent hydrogens with different coupling constants. (C) Ha is coupled to three nonequivalent hydrogens with identical coupling constants. (D) Ha is coupled to three nonequivalent hydrogens with different coupling constants. (E) Ha is coupled to three equivalent hydrogens with identical coupling constants.

57. Which of the following combinations of reactants would produce a meso compound? (A) Cis-3-hexene and Br2 (B) Trans-3-hexene and Br2 (C) Cis-3-hexene and Br2 in H2O (D) Trans-3-hexene and Br2 in H2O (E) Trans-3-hexene and H2/Pd/C

58. What is the product of the following sequence of reactions? (A) 1,1-Diethylcyclopropane (B) Cis-1,2-diethylcyclopropane (C) Trans-1,2-diethylcyclopropane (D) Cis and trans-1,1-diiodo-2,3-diethylcyclopropane (E) Cis-1,2-diethyl-3,3-diiodocyclopropane

59. An unknown hydrocarbon shows a parent peak on the mass spectra at m/z = 86. There is no evidence of absorption from visible or UV spectra. The IR shows no major absorption outside the C-H stretch and bending vibration. The 1 H NMR reveals a singlet at δ 0.9 (9H), a triplet at 0.98 (3H) and a quartet at 1.6 (2H). Which compound below best fits the description? 

60. Which statement is correct for the reaction shown below? 1-chloro-2,4-dinitrobenzene + NaOH → 2,4-dinitrophenol (A) This reaction is an electrophilic aromatic substitution. (B) This reaction is a SN1 substitution. (C) This reaction is a nucleophilic aromatic substitution. (D) Substituted benzyne is the reaction intermediate. (E) None of the above. II. Choose one correct answer for the following questions