67. How many net numbers of spheres are occupied in a face-centered cubic (f.c.c.) unit cell?
(A) 1
(B) 2
(C) 4
(D) 6
(E) 8

63. Determine the number of nodal surfaces for a 3s orbital. (A) 3 (B) 2 (C) 1 (D) 0 (E) None of these

64. Which molecule has only one resonance structure that obeys the Octet rule? (A) NO+ (B) NO2 − (C) NO3 − (D) O3 (E) CO32−

65. What is the resonance frequency (MHz) for 13C nuclei operated in a nuclear magnetic resonance spectrometer of 400 MHz? (gyromagnetic ratio of 1 H and 13C is ~4) (A) 100 (B) 200 (C) 400 (D) 800 (E) 1600

66. The color difference between [CoCl4]2− and [Co(H2O)6]2+ can be supported by which concept? (A) Redox process (B) Spectrochemical series (C) Disproportionation reaction (D) van’t Hoff factor (E) Hard-Soft Acid-Base

68. For a reaction involving changes of reactant concentrations ([A]), what is the reaction order (m) when the correlation of ln [A] versus time (t) is a straight line? (A) m=0 (B) m=1/2 (C) m=1 (D) m=2 (E) None of these

69. Consider the reaction Fe3+(aq) + SCN- (aq) FeSCN2+(aq). Which one of the following statements is correct? (A) The equilibrium position shifts to the right after water is added to double the volume (B) The equilibrium position shifts to the right after AgNO3(aq) is added (C) The equilibrium position shifts to the left after NaOH(aq) is added (D) The equilibrium position shifts to the left after Fe(NO)3(aq) is added (E) None of the above is correct

70. Which “P” in the following compounds has the lowest oxidation state? (A) Phosphoric acid (B) Phosphorous acid (C) Hypophosphorous acid (D) Sodium phosphide (E) Black phosphorus

71. How many π electrons are delocalized in 1,4-diphenyl-1,3-butadiene? (A) 4 (B) 8 (C) 16 (D) 24 (E) 32

72. Based on MO theory, which molecule is not paramagnetic? (A) O2− (B) O2 + (C) O2 (D) N2 (E) N2+

73. Consider mixing equal volume of 0.1 M Na2CO3 solution and 0.1 M H2SO4 solution. Which statement is correct? (A) [H+ ] is less than 0.05 M (B) [H+ ] is between 0.1 M and 0.05 M (C) [H+ ] is 0.1 M (D) [H+ ] is 0.2 M (E) pH ＞ 7