64. Select the Lewis structure for XeO2F2 which correctly minimizes formal charges.
(A)
(B)
(C)
(D)
(E)

30. Which of the following is an example of nitrogen fixation? (A) Absorption of NH3 and its transformation into to N2. (B) Absorption of NH3 and its transformation into to NO2. (C) Absorption of N2 and its transformation into elemental nitrogen. (D) Absorption of N2 and its transformation into NH3. (E) Absorption of nitric acid and its transformation into N2.

複選題61. A solution contains the ions Ag+ , Ba2+, and Ni2+. Dilute solutions of NaCl, Na2SO4, and Na2S are available to separate the positive ions from each other. In order to effect separation, the solutions should be added in which order? (A) Na2S, NaCl, Na2SO4 (B) Na2SO4, NaCl, Na2S (C) Na2SO4, Na2S, NaCl (D) NaCl, Na2S, Na2SO4 (E) NaCl, Na2SO4, Na2S

62. Which of the statements below correctly describes the combustion of glucose, shown below? (A) Hydrogen in C6H12O6 is being reduced. (B) Oxygen in O2 is being oxidized. (C) Hydrogen in C6H12O6 is the reducing agent. (D) Oxygen in C6H12O6 is the oxidizing agent. (E) Carbon in C6H12O6 is being oxidized.

63. Reaction intermediates differ from activated complexes in that ________. (A) they are stable molecules with normal bonds and are frequently isolated (B) they are molecules with normal bonds rather than partial bonds and can occasionally be isolated (C) they are intermediate structures which have characteristics of both reactants and products (D) they are unstable and can never be isolated (E) all reactions involve reaction intermediates, but not all have activated complexes

65. Which species has the highest bond order? (A) NO+ (B) O2 (C) O2 − (D) O2 2− (E) NO−

66. What hybridization is present in the phosphorus atom in PCl3 and PCl5, respectively? (A) sp 2 , d 2 sp 3 (B) sp 2 , dsp3 (C) dsp, dsp3 (D) sp 3 , d 2 sp 3 (E) sp 3 , dsp3

67. The spectrochemical series is I– < Br– < Cl– < F– < OH– < H2O < NH3 < en < NO2– < CN– . Which of the following complexes will absorb visible radiation of the highest energy? (A) [Co(H2O)6] 3+ (B) [CoI6] 3– (C) [Co(OH)6] 3– (D) [Co(en)3] 3+ (E) [CoCl6] 3– 

68. A diprotic acid H2A has Ka1 = 1 x 10–4 and Ka2 = 1 x 10–8 . The corresponding base A2– is titrated with aqueous HCl, both solutions being 0.1 mol/L. Which one of the following diagrams best represents the titration curve which will be seen? (A)(B) (C) (D) (E)

69. Which of the following coordination compounds will form a precipitate (AgCl) when treated with an aqueous solution of AgNO3? (A) [Cr(NH3)3Cl3] (B) [Cr(NH3)Cl]SO4 (C) Na3[Cr(CN)6] (D) [Cr(NH3)6]Cl3 (E) None of the above.

70. If a complex ion is square planar, which d-orbital is highest in energy? (A) dx2-y2 (B) dx2 (C) dxy (D) dyz (E) dxz