39. What is the major product of the following reaction?
(A)
(B)
(C)
(D) 

35. Arrange these carbocations in order of increasing stability (least to most). (A) I, II, III(B) I, III, II(C) II, I, III(D) III, II, I

36. Which of the following alkenes is the major product when 2-bromo-2-methylpentane is treated with sodium ethoxide in ethanol? (A) 2-methylpent-1-ene(B) 2-methylpent-2-ene(C) (E)-4-methylpent-2-ene (D) (Z)-4-methylpent-2-ene

37. Which of the following alkenes is the major product when 2-bromo-2-methylpentane is treated with potassium tert-butoxide in tert-butanol? (A) 2-methylpent-1-ene(B) 2-methylpent-2-ene(C) (E)-4-methylpent-2-ene (D) (Z)-4-methylpent-2-ene

38. Which of the following statements applies to the E2 mechanism? (A) It occurs with inversion of stereochemistry. (B) It occurs with racemization of stereochemistry. (C) It proceeds through the more stable carbocation intermediate. (D) The C-H and C-X bonds that break must be anti.

40. Provide the reagents necessary to complete the following transformation. (A) 1. BH3∙THF 2. H2O2, HO- (B) H2O, H2SO4 (C) OsO4, H2O2 (D) CH3CO3H

41. Which of the following reagents will convert 1 mole of 3-methylpent-1-yne into 3-methylpentane?(A) 1 mole of Br2 in CCl4 (B) 2 moles of Cl2 in CCl4 (C) 2 moles of HCl (D) 2 moles H2, Ni and heat

42. Which of the following reagents should be used to convert  hex-3-yne to (Z)-hex-3-ene?(A) H2, Pt(B) Na, NH3(C) H2, Lindlar's catalyst (D) H2SO4, H2O

43. Which of the following statements correctly pertains to a pair of enantiomers? (A) They rotate the plane of polarized light by exactly the same amount and in opposite directions. (B) They rotate the plane of polarized light by differing amounts and in opposite directions. (C) They rotate the plane of polarized light by differing amounts and in the same direction. (D) The have different melting points. 

44. Predict the specific rotation of the compound shown. (A) It is impossible to predict； it must be determined experimentally. (B) Because both asymmetric centers are R, the compound is dextrorotatory. (C) Because both asymmetric centers are S, the compound is levorotatory. (D) Zero； the compound is achiral.

45. What is the major difference between an antiaromatic and aromatic compound? (A) Only aromatic compounds follow Huckle's rule. (B) Antiaromatic compounds have at least one sp3 hybridized atom in the ring. (C) Antiaromatic compounds can assume a chair-like structure while aromatic compounds are nearly flat. (D) Aromatic compounds cannot have a charged atom in the structure.