80. What is the highest occupied molecular orbital of a C₂^4- ion?
(A)σ_2s^*
(B) π_2p
(C) σ_2p
(D)π_2p^* 
(E) σ_2p^*

76. How can we explain the fact that CCl4 is a liquid and CL. is a solid at 25℃? Which of the following options is the best explanation? (A) CCl4 has a larger dipole moment than Cl4 due to the higher electronegativity of CI compared to I. (B) Cl4 has a larger dipole moment than CCl4 because there is stronger electron repulsion in the Cl-I bonds than in the C-CI bonds. (C) London dispersion forces are stronger in C Cl4 than in  Cl4 because Cl is more electronegative than I. (D) London dispersion forces are stronger in  Cl4 than in C Cl4 because  Cl4 has a more easily polarizable electron cloud. (E) None of the above. 

77. How many microstates does a s1d1 electron configuration have? (A)5(B)10 (C)15 (D) 20 (E) 25

78. The most probable distribution function for a system of molecules is given by (A) Maxwell-Boltzmann distribution (B) Fermi-Dirac distribution (C) Bose-Einstein distribution (D) All of the above (E) None of the above 

79. What is the oxidation state of the terminal nitrogen atom in azide ions? (A)-3 (B)-1 (C)+1 (D) +4 (E)+5 

81. On the basis of VSEPR, what is the predicted point group for XeO2F2? (A)Ci (B) Cs (C)C2v (D) C4v (E) D3h

82. Sort the ions in the order from the largest radius to the smallest radius:(1) Se2- (2) Br- (3) Rb+ (4) SR2+ (A)1,2,3,4 (B)4,3,2,1 (C)3,1,2,4 (D)3,2,1,4 (E) 3,1,4,2

83. What is the highest molecular orbital degeneracy of cyclic H3+? (A)0(B)1 (C)2 (D)3 (E)4

84. Which of the following [M(H2O)o"* complexes reacts the slowest in a water exchange reaction? (A) Cu2+ (B) High-spin Fe3+ (C) V3+(D) Ti3+ (E) Cr3+ 

85. How many carbonyI stretching bands could be observed in the IR spectrum of the [Co(CO)3(PPh3)2]+ complex exhibiting a trigonal bipyramidal molecular geometry, where all three CO ligands are in the equatorial plane? (A)1 (B) 2 (C)3 (D)4 (E) 5 

86. The infrared spectrum of synthesized [Co(CO)2(CN)2Br2]- exhibits two bands attributable to C-O stretching but only one band attributable to C-N stretching. What is the most likely arrangement of the coordinated CO and CN ligands around the Co center, respectively? (A) cis C-O, trans C-N (B) cis C-O, cis C-N (C) trans C-O, cis C-N (D) trans C-O, trans C-N (E) None of the above