38. In the titration of a weak acid HA with 0.100 M NaOH the stoichiometric point is known to occur at a pH value of approximately 10. Which of the following indicator acids would be best to use to mark the endpoint of this titration?
(A) indicator A, 10^-14
(B) indicator B,iTa= 10^-11  
(C) indicator C,Ka= 10^-8
(D) indicator D, Ka = 10^-6
(E) none of these

34. If, at a given temperature, the equilibrium constant for the reaction  is Kp, then the equilibrium constant for the reactioncan be represented as: (A) (B)  (C) (D) (E) none of above

35. The value of the equilibrium constant, K, is dependent on | . The temperature of the system. II • The nature of the reactants and products. Ill. The concentration of the reactants. IV. The concentration of the products. (A)丨，|| (B) II，III (C) III，IV (D) It is dependent on three of these choices. (E) It is not dependent on any of these choices.

36. Which of the following would produce a basic aqueous solution? (A)P4O10 (B)KC1 (C) C02 (D) NH4C1 (E) none of these

37. Which of the following will not produce a buffered solution? (A) 100mLof0.1MNa2C03and50mLof0.1 MHC1 (B) 100 mL of 0.1 MNaHCO3, and 25 mL of 0.2M HC1 (C) 100 mL of 0.1 M Na2CO3, and 75 mL of 0.2 M HC1 (D) 50 mL of 0.2 M Na2CO3 and 5 mL of 1.0 M HC1 (E) lOOmLofO.l MNa2C03 and50mLof0.1 MNaOH

39. Silver acetate (AgC2H3O2)is a sparingly soluble salt with Ksp = 1.9 ✖ 10- 3. Consider a saturated solution in equilibrium with the solid salt. Compare the effects on the solubility of adding to the solution either the acid HNO3, or the base NH3. (A) Either substance would decrease the solubility. (B) NH3 would increase the solubility, but HNO3, would decrease it. (C) NH3 would increase the solubility, but HN03 would have virtually no effect. (D) Either substance would increase the solubility. (E) NH3 would decrease the solubility, but HN03 would increase it. .

40. Which of the following compounds is an achiral compound?(A)(B)(C)(D)(E)

41. Indicate the alcohols (or acids) has the lowest pKa value? (A) 2,2,2-trifluoroethanol (B) 2,2-dimethylpropanol (C) 2,2,2-trichloroethanol (D) cyclopropanol (E) cyclohexanol

42. Consider the NMR spectrum of BA, which is shown below. The formula of compound BA is C8H7C1O.The structure of BA is (A)(B)(C)(D)(E) None of the above .

43. When compound I was heated in ethanol, an ether product was collected (shown below)The mechanism of this reaction is (A) SN2 (B) E2 (C) SN1 (D) El (E) none of above

44. To complete the following reaction, please choose the best reaction condition? (A) B2H6then H2O2/Na0H (B) HC1 (C)OsO4 then H2O2(D) O3 then Me-S-Me (E) Hg(OAc)2 then NaBH4