84. What is the structural relationship of the following two compounds?

(A) not isomers
(B) conformational isomers
(C) cis-trans isomers
(D) structural isomers
(E) both conformational isomers and structural isomers

80. A formula of a certain compound is [M(NH3)5Cl]Cl2, where the M is a type of metal. The metal ion has 24 electrons in this complex. Determine the identity of the metal. (A) Mn (B) Fe (C) Co (D) Ni (E) Cu

81. Two well-known complex ions containing Ni are , which is green, and , which is purple. Which one of the following statements is true? (A) The crystal field splitting energy (△) is greater for than for . (B) absorbs energy in the red region of the spectrum. (C) Both complex ions are diamagnetic. (D) transmits light with wavelengths of approximately 650–700 nm. (E) The green complex absorbs green light.

82. Which of the labeled C-H bond is the weakest? (A) I (B) II (C) III (D) IV (E) V

83. Which of the following alkenes generates the greatest heat upon hydrogenation? (A) 1,3-pentadine (B) 1,4-pentadiene (C) 1,3-butadiene (D) cis-2-pentene (E) trans-2-pentene

85. A tetracyclic compound, aldrin , was used as an insecticide. How many double bonds are presented in aldrin? (A) 1 (B) 2 (C) 3 (D) 4 (E) 5

86. Which of following structures presents the most stable conformation of cis-1-ethyl-2-isopropylcyclohexane? (A) (B) (C) (D) (E)

87. Determine the most acidic compound shown below. (A) A (B) B (C) C (D) D (E) There is not enough information to determine the acidic order.

88. Peramivir has shown to be effective against the influenza B virus. Rank following nitrogen atoms in the order from the strongest base to the weakest base. (A) 1 ＞ 3 ＞ 2 (B) 2 ＞ 1 ＞ 3 (C) 2 ＞ 3 ＞ 1 (D) 3 ＞ 2 ＞ 1 (E) 3 ＞ 1 = 2

89. Arrange the following arenes in the decreasing reactivity toward HNO3/H2SO4. (a) PhH (b) PhCl (c) PhCO2H (d) PhCH3 (A) (c) ＞ (d) ＞ (b) ＞ (a) (B) (a) ＞ (b) ＞ (d) ＞ (c) (C) (d) ＞ (a) ＞ (b) ＞ (c) (D) (d) ＞ (b) ＞ (a) ＞ (c) (E) (a) ＞ (b) ＞ (c) ＞ (d)

90. Which compound exhibits only two signals in its 1H NMR spectrum, a triplet and a quintet? (A) BrCH2CH2CH2Br (B) BrCH2CH2CH2Cl (C) (CH3)2CHCH(CH3)2 (D) CH3CH2CH2CH3 (E) (CH3)2CHOCH(CH3)2