72. Which of the following molecules is an optically active molecule?
(A)
(B)
(C)
(D)
(E) None of the above.

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

71. Which of the following statement is incorrect about hydrocarbons? (A) Breaking the C─H bonds separately of CH4 requires different energies. (B) The average C─H bond energy of CH4 is higher than that of H─H. (C) Hydrocarbons are hydrophobic. (D) Longer alkanes are with higher viscosities than shorter ones. (E) Branched alkanes are with lower boiling points than their corresponding straight isomers.

73. The structure below is the repeating unit of a (A) homopolymer formed by an addition reaction. (B) homopolymer formed by a condensation reaction. (C) copolymer formed by an addition reaction. (D) copolymer formed by a condensation reaction. (E) polyester formed by an addition reaction.

74. Identify the products of the reaction of 3-octene with chlorine. (A) (B) (C) (D) (E)

75. Which of the following statements about molecular spectroscopies is incorrect? (A) Ultraviolet-visible (UV-vis) spectra provides information about HOMO-LUMO gap. (B) Infrared (IR) spectra gives information on bond vibrational transitions. (C) Rotation transitions occur in the microwave region. (D) Nuclear magnetic resonance (NMR) spectra provides information about the electronic transitions. (E) UV-vis spectra involves both the molecular ground state and the excited state.

76. Consider the following reaction:. The equilibrium constant K is about 0.0196 at 115 °C. Calculate Kp at this temperature? (A) 0.196 (B) 0.624 (C) 0.285 (D) 22.9 (E) 2.9

77. The equilibrium constant for reaction (A) K 4 (B) 4K (C) 1/4 K (D) 1/K4 (E) - K 4 

78. The pH of a 0.005 M K2O aqueous solution should be ________. (A) 11.7 (B) 7.0 (C) 2.3 (D) 12.0 (E) 5.0