72. What is the major product for the following reaction 
(A) 
(B) 
(C) 
(D)  
(E) 

68. The HOMO of (2E,4Z,6E)-octatriene undergo thermal cyclization using which process and which product? (HOMO orbital of pi-electrons of octatriene is given below, not showing the stereochemistry) (A) disrotatory and cis-product (B) conrotatory and cis-product (C) disrotatory and trans-product (D) conrotatory and trans-product (E) both disrotatory and conrotatory to give trans and cis product respectively

複選題69. Assuming kinetic conditions, provide a structure for the major product of the reaction below. Include correct stereochemistry. ?  (A) I (B) II (C) III (D) IV (E) V

70. Predict the major product of the following reaction. OH CHO OH acid cat. ? (A)  (B)(C) (D)  (E)

71. Identify the monomer(s) which are used to prepare the following segment of polymer: - CH2CH=CHCH2CH(C6H5)CH2CH2CH=CHCH2CH(C6H5)CH2- (A) CH2=CH2 and CH2=CHC6H5 (B) CH2=CHCH=CH2 and CH2=CHC6H5 (C) CH2=C(C6H5)CH=CH2 (D) C6H5CH=CHCH=CH2 (E) CH2=C=CH2 and CH2=CHC6H5

73. Which is the best procedure for the preparation of 2,4-dinitrobenzoic acid from benzene? (A) 1. HNO3/H2SO4 2. CH3Br/AlCl3 3. HNO3/H2SO4 4. KMnO4/H+ (B) 1. CH3Br/AlCl3 2. HNO3/H2SO4 3. KMnO4/H+ 4. HNO3/H2SO4 (C) 1. CH3Br/AlCl3 2. KMnO4/H+ 3. HNO3/H2SO4 (excess) (D) 1. HNO3/H2SO4 2. CH3Br/AlCl3 3. KMnO4/H+ 4. HNO3/H2SO4 (E) 1. CH3Br/AlCl3 2. HNO3/H2SO4 (excess) 3. KMnO4/H+

74. Predict the major product for the following reaction. (A) I (B) II (C) III (D) IV (E) II & IV

75. Which of the following molecules below best fits the fragmentation pattern of the mass spectrum below.  (A) I (B) II (C) III (D) IV (E) V

76. Choose the structure that is NOT an intermediate or product in the Wolff-Kischner reduction of acetophenone. (A)(B)(C)(D)(E)

77. Choose the best alkyne reactant to complete the following reaction sequence. (A)(B)(C)(D)(E)

78. Extraction of a mixture of toluene, phenol and phenylacetic acid under various conditions can be used to separate them. What are the correct compound X, Y and Z from the separation scheme.  (A) (X)-toluene; (Y)-phenylacetic acid; (Z)-phenol (B) (X)-toluene; (Y)-phenol; (Z)-phenylacetic acid (C) (X)-phenylacetic acid; (Y)-toluene; (Z)-phenol (D) (X)-phenol; (Y)-toluene; (Z)-phenylacetic acid (E) (X)-phenylacetic acid; (Y)-phenol; (Z)-toluene