SOLVED

41) Which of the following is a logical inference from the fact that a 0.10 molar solution of potassium acetate, KC2H3O2, is less alkaline than a 0.10 molar solution of potassium cyanide, KCN? A) Hydrocyanic acid is a weaker acid than acetic acid. B) Cyanides are less soluble than acetates. C) Hydrocyanic acid is less soluble in water than acetic acid. D) Acetic acid is a weaker acid than hydrocyanic acid. E) 0.10 M potassium acetate is more concentrated than 0.10 M potassium cyanide. 42) Determine the pH of 263 ml of solution which has [NH4I] = 0.300 M. Kb = 1.74 × 10-5 for NH3(aq). A) 2.6 B) 11.4 C) 4.9 D) 9.1 E) 4.6 43) The pH of a solution of NH4C2H3O2 is approximately 7. The best explanation is: A) This salt does not react with water. B) Ammonium acetate is a weak electrolyte. C) All salts of weak acids and weak bases are neutral. D) Aqueous ammonia and acetic acid have approximately equal ionization constants. E) The salt is a product of a strong acid and a strong base. 44) Which indication of relative acid strengths is INCORRECT? A) HCl > HF B) HClO2 > HClO C) H2SO4 > H2SO3 D) H2SO3 > HNO3 E) CH3CO2H > CH3CH2OH 45) Which of the following statements concerning aqueous solutions of salts is FALSE? A) For any salt of a strong acid and a strong base, the pH will be about 7. B) For any salt of a strong acid and a weak base, the pH will be <7. C) For any salt of a weak acid and a strong base, the pH will be >7. D) For any salt of a weak acid and a weak base, the pH will be about 7. 46) Which of the following are Lewis bases? I) BCl3 II) H- III) H2O IV) NH3 V) AlCl3 A) II), III) and IV) B) I), II), and III) C) III), IV) and V) D) I), II), and V) E) I), II), and IV) 47) The concept of an acid not limited to H+ or species containing one or more protons is inherent in: A) only the Arrhenius theory B) both the Arrhenius and the Br∅nsted-Lowry theories C) only the Br∅nsted-Lowry theory D) both the Br∅nsted-Lowry and the Lewis theories E) only the Lewis theory 48) In the reaction BF3 + NH3 ? F3B:NH3, BF3 acts as: A) an Arrhenius base B) a Lewis base C) a Br∅nsted acid D) a Lewis acid E) an Arrhenius acid 49) Which species in the following reaction acts as a Lewis acid? CuSO4(s) + 4NH3(aq) ? [Cu(NH3)4]2+(aq) + SO42-(aq) A) SO42- B) Cu2+ C) [Cu(NH3)4]2+(aq) D) NH3 E) [Cu(NH3)4]2+(aq) and SO42- 50) In which of the following cases is water acting as a base under the Lewis definitions, but not under the Br∅nsted-Lowry definitions? A) H2O(l) + HF(g) ? H3O+(aq) + F(aq) B) H2O(l)+ CN-(aq) ? OH-(aq) + HCN(aq) C) H2O(l) + Cu2+(aq) ? Cu(H2O)2+(aq) D) H2O(l) + PO43-(aq) ? 2OH-(aq) + H2PO4-(aq) E) H2O(l) [electrolysis] ? 2H2(g) + O2(g)