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

38. A pure sample of (S)-phenylalanine has a specific rotation of +70o . A mixture of the two enantiomers of phenylalanine gives a specific rotation of -7.0o . What are the percentages of the S and R enantiomers in the mixture? (A) 75 % S, 25 % R (B) 65 % S, 35 % R (C) 55 % S, 45 % R (D) 45 % S, 55 % R (E) 35 % S, 65 % R

39. Which of the following compounds would you expect to show IR absorptions at 1735, 2100, 3300 cm-1? 

40. Which of the following compounds would most likely be used in the preparation of isobutylbenzene from benzene?  (A) (CH3)2CHCOCl (B) (CH3)2CHCH2Cl (C) (CH3)2CHCH2Br  (D) CH3CH2CH2CH2Cl (E) CH3CH2CH2COCl

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

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

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

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.