45. Which of the labeled H atoms (1-5) in the following molecule would be predicted to be the most acidic? 

 
(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

41. What is the product of the following reaction?  (A) acetaldehyde (B) acetic acid (C) racemic (2R,3R) and (2S,3S)-2,3-butanediol (D) meso-2,3-butanediol (E) cis-2,3-epoxybutane

42. Provide the structure of the major organic product in the following reaction:

43. Which of the following describes the most stable conformation of trans-1-isopropyl-3-methylcyclohexane? (A) Both groups are equatorial. (B) Both groups are axial. (C) The isopropyl group is equatorial and the methyl group is axial. (D) The isopropyl group is axial and the methyl group is equatorial. (E) none of the above

44. Which of the following compounds will react most rapidly with HCl?(A) 5-methyl-1-hexene(B) 4-methyl-1-hexene(C) ( E )5-methyl-2-hexene(D) ( E )-2-methyl-3-hexene(E) 2-methyl-2-hexene

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

47. Which of the following compounds exhibits the pattern of m/z values shown below? 41, 43, 57, 87, 101, 116 (A) n-propylbromide (B) isopropyl bromide (C) 2-hexanol (D) 2-butanone (E) sec-butyl isopropyl ether

48. Which of the following statements correctly pertains to a pair of enantiomers? (A) They rotate the plane of polarized light by exactly the same amounts 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 directions. (D) They have the same specific rotation, but they have different melting points. (E) They have the same melting points, but they have different boiling points.

49. Which of the following compounds is the most reactive toward electrophilic aromatic substitution?

50. What is the product of the following reaction? 

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