67. Which one of the following has the weakest conjugate base?
(A)HF (K_a = 6.8 × 10^-4)
(B)HClO (K_a = 3.0 × 10^-8)
(C) HNO₂ (K_a = 4.5 × 10^-4)
(D)HCN (K_a = 4.9 × 10^-10)

63. In which one of the following solutions is silver chloride the most soluble? (A)0.200 M HCl (B)0.750 M LiNO3 (C) 0.0150 M NH3(D)0.185 M KCl

64. A result of the common-ion effect is ________. (A)that some ions, such as Na+ (aq), frequently appear in solutions but do not participate in solubility equilibria (B)that common ions, such as Na+ (aq), don't affect equilibrium constants (C) that the selective precipitation of a metal ion, such as Ag+, is promoted by the addition of an appropriate counterion (X-) that produces a compound (AgX) with a very low solubility (D)that ions such as K+ and Na+ are common ions, so that their values in equilibrium constant expressions are always 1.00

65. A Br∅nsted-Lowry base is defined as a substance that ________. (A)increases [H+] when placed in H2O (B)decreases [H+] when placed in H2O (C) increases [OH-] when placed in H2O(D)acts as a proton acceptor

66. The hydride ion, , is a stronger base than the hydroxide ion, O . The product(s) of the reaction of hydride ion with water is/are ________. (A)H3O+ (aq) (B)OH- (aq) + H2 (g) (C) OH- (aq) + 2H+ (aq)(D)no reaction occurs

68. Which one of the following will change the value of an equilibrium constant? (A)changing temperature (B)adding other substances that do not react with any of the species involved in the equilibrium (C) varying the initial concentrations of reactants (D) varying the initial concentrations of products

69. The equilibrium constant for the gas phase reactionis Keq = 4.34 × 10-3 at 300 °(C) At equilibrium, ________. (A)products predominate (B)reactants predominate (C) roughly equal amounts of products and reactants are present(D)only products are present

複選題70. Consider the following reaction at equilibrium:Le Châtelier's principle predicts that the moles of in the reaction container will increase with ________. (A)some removal of from the reaction vessel (V and T constant) (B)a decrease in the total pressure (T constant) (C) addition of some to the reaction vessel (V and T constant) (D) a decrease in the total volume of the reaction vessel (T constant)

71. Of the following, all are valid units for a reaction rate except ________. (A)mol/L (B)M/s (C) mol/hr(D)g/s

72. When argon is placed in a container of neon, the argon spontaneously disperses throughout the neon because ________. (A)of the large attractive forces between argon and neon atoms (B)of hydrogen bonding (C) a decrease in energy occurs when the two mix (D) the dispersion of argon atoms produces an increase in disorder

73. When solutions of strong electrolytes in water are formed, the ions are surrounded by water molecules. These interactions are described as a case of ________. (A)hydration (B)supersaturation (C) crystallization(D)dehydration