Acid and base review

Acids and Bases Review CHEMISTRY 12 Page ACID-BASE REVIEW ANSWERS 1. 2. 3. 4. 5. D A C B B 31. 32. 33. 34. 35. C A A C B 61. 62. 63. 64. 65. D A D C A 91. 92. 93. 94. 95. D B A B A 6. 7. 8. 9. 10. B C A A A 36. 37. 38. 39. 40. B C D B B 66. 67. 68. 69. 70. C D C B D 96. 97. 98. 99. 100. B C B C D 11. 12. 13. 14. 15. D B C D A 41. 42. 43. 44. 45. B B A D A 71. 72. 73. 74. 75. A D A B D 101. 102. 103. 104. 105. C D C A C 16. 17. 18. 19. 20. D A B A B 46. 47. 48. 49. 50. C A C C A 76. 77. 78. 79. 80. D D B C D 106. 107. 108. 109. 110. D B B C A 21. 22. 23. 24. 25. C D B A D 51. 52. 53. 54. 55. A B B D B 81. 82. 83. 84. 85. A A D C A 111. 112. 113. 114. B D C D 26. 27. 28. 29. 30. B D C D A 56. 57. 58. 59. 60. C D C B B 86. 87. 88. 89. 90. B C D D C 115. 116. 117. 118. 119. A A D A C Written responses 1. 1.4 x 10-5 2. 3.0 x 10-8 3. HS-(aq) + H2O (l) Reactants 4. 4.2 x 10-9 5. 7.2 x 10-11 M 6. 2.9 x 10-2 M  H2S (aq) + OH- (aq) Acids and Bases Review Page 7. Use a pH indicator or meter. A lower pH indicates a higher [H+] which means greater dissociation which means stronger acid. 8. a) It's much easier to remove first proton. b) H2SO4  H+ + HSO4- Ka very large HSO4-  H+ + SO42- Ka not as large 9. 4.30 10. 1.3 x 10-4 11. base, acid, acid, base reactants 12. 2.29 13. a) HCO3-(aq) + SO32-(aq)  CO32-(aq) + HSO3-(aq) b) HCO32- 14. H+(aq) + OH-(aq) 15. 13.44 16. basic because Kb > Ka 17. 0.76 grams 1 8. to prevent rapid changes in pH due to addition of H+ or OH- ions. 19. S (s) + O2 (g)  SO2 (g) 2SO2 (g) + O2 (g)  2SO3 (g) SO3 (g) + H2O (l)  H2SO4 (l) 20. 60 g/mol 21. 0.044 M 22. SrO (s) + H2O (l) 23. SO2 produces acid rain. This acidifies lakes which kills fish. (It also destroys plant roots and damages leaves.) SO2 (g) + H2O (l)  H2SO3 (aq) or 2 SO2 (g) + O2 (g) + 2 H2O (l)  2 H2SO4 (aq)   H2O (l) Sr2+(aq) + 2 OH-(aq) Acids and Bases Review CHEMISTRY 12 Page ACIDS AND BASES REVIEW Part I: 1. Which one of the following is the conjugate base of HPO42- ? a) b) c) d) 2. In the following equation, what is the correct order for Bronsted acids and bases ? HS- + H2SO3 H2S + HSO3a) b) c) d) 3. It more readily accepts protons. It less readily accepts protons. It more readily donates protons. It less readily donates protons. HCl HNO2 HNO3 H2SO4 What is the [H3O+] in an aqueous solution of 4.00 x 10-4 M NaOH ? a) b) c) d) 6.  acid + base  base + acid  acid + base  base + acid The following acids are all 1 M concentration. Which acid has the smallest hydronium ion (H3O+) concentration ? a) b) c) d) 5. base + acid base + acid acid + base acid + base Which one of the following statements is true about the stronger of two acids ? a) b) c) d) 4. HPO4H2PO4H3PO4 PO43- 2.5 x 10-12 M 2.5 x 10-11 M 2.5 x 10-10 M 4.0 x 10-4 M The indicator bromthymol blue has a Ka of 1.00 x 10-7. If a 2.00 x 10-3 M solution of the indicator is used, what will be the [H3O+] at the end point (transition point), at the intermediate colour between yellow and blue ? a) b) c) d) 2.00 x 10-10 M 1.00 x 10-7 M 5.00 x 10-5 M 3.16 x 10-4 M Acids and Bases Review 7. What is the pH of a 0.0100 M hydrochloric acid (HCl) solution ? a) b) c) d) 8. 12. 1.0 x 10-12 M 1.0 x 10-2 M 2.00 M 12.0 M Which one of the following is the conjugate base of H2PO4- ? a) b) c) d) 11. pOH = - log [OH-] pOH = - log [OH-]2 pOH = - log (1/[OH-]) pOH = log [OH-] What is the hydronium ion concentration, [H3O+], of an aqueous solution whose pH is 12.00 ? a) b) c) d) 10. 1.00 x 10-2 0.0100 2.000 12.000 Which one of the expressions given below is the correct expression for calculating pOH ? a) b) c) d) 9. Page HPO42H3PO4 PO43H3PO3 The following equation represents the dissociation of an aqueous solution of the base methylamine, CH3NH2 : CH3NH2 (aq) + H2O(l)  CH3NH3+(aq) + OH-(aq) Which one of the following is the correct expression for the Kb of methylamine ? a) Kb = [CH3NH2][OH-] -----------------[CH3NH3+] b) Kb = [CH3NH3+][CH3NH2][OH-] c) Kb = [CH3NH3+][CH3NH2] -----------------------[OH-] d) Kb = [CH3NH3+][OH-] -------------------[CH3NH2] Data : 1. HClO(aq) + H2O(l)  H3O+(aq) + OCl-(aq) 2. Ka (HClO) = 3.00 x 10-8 When the equilibrium concentration of a hypochlorous acid solution is 1.00 x 10-2 M , what is the pH of the solution ? a) b) c) d) 2.000 4.761 9.239 9.523 Acids and Bases Review 13. What is the Ka of a 0.200 M solution of a weak acid which is found to have a pH of 5.62 ? a) b) c) d) 14. 0.010 M HCl 0.10 M HBr 0.10 M HI 0.10 M HF Which one of the following equations shows the basic form of an indicator HIn reacting in an acidic solution? a) b) c) d) 18. acid + base acid + base acid + base  base + acid base + acid acid + base base + acid  base + acid Which one of the following is the weakest acid ? a) b) c) d) 17. As a Bronsted acid donating protons. As a Bronsted acid accepting protons. As a Bronsted base donating protons. As a Bronsted base accepting protons. Which one of the following is the correct order for Bronsted acids or bases in the equation HSO3- + HPO42-  H2PO4- + SO32- ? a) b) c) d) 16. 5.8 x 10-12 8.7 x 10-11 2.9 x 10-11 1.2 x 10-5 In the equation NH4+ + H2O H3O+ + NH3 , how does the H2O act ? a) b) c) d) 15. Page In-(aq) + H3O+(aq)  HIn(aq) + H2O(l) HIn(aq) + H3O+(aq)  H2In+(aq) + H2O(l) In-(aq) + H2O(l) HIn(aq) + OH-(aq) HIn(aq) + OH-(aq)  In-(aq) + H2O(l) The indicator methyl red has a Ka of 4.00 x 10-6. If a 1.00 x 10-3 molar solution of the indicator is used, what will be the [H3O+] at the endpoint, where the colour is orange (i.e. intermediate between red and yellow) ? a) b) c) d) 4.00 x 10-9 M 4.00 x 10-6 M 2.00 x 10-3 M 4.00 x 10-3 M Acids and Bases Review 19 Page Which one of the following statements about HNO3 and HNO2 is TRUE, given that HNO3 is a stronger acid than HNO2 ? a) NO2- ion is a stronger base than NO3- ion. b) NO3- ion is a better proton accepter than NO2- ion. c) The bond between H and O in undissociated HNO3 is stronger than the bond between H and O in undissociated HNO2. d) A solution of 1 M HNO3 contains fewer particles than a solution of 1 M HNO2 if equal volumes are compared. 20. What is the hydronium ion concentration, [H3O+], of a solution whose pH is 6.00? a) b) c) d) 21. What is the pOH of a 0.012 M solution of sodium hydroxide, NaOH ? a) b) c) d) 22. 1.0 x 10-8 M 1.0 x 10-6 M 6.0 M 1.0 x 106 M 1.03 1.9 1.92 12.08 The conjugate acid of HPO42- is a) b) c) d) H+ PO43H3PO4 H2PO4- Acids and Bases Review Page Refer to the following information when answering questions 37 & 38 HNO2 (aq) + H2O (l)  H3O+(aq) + NO2-(aq) Ka HNO2 = 5.1 x 10-4 23. What is the pH of an aqueous solution of nitrous acid, HNO2, when its equilibrium concentration is 1.0 x 10-3 M ? a) b) c) d) 23. What is Kb for the nitrite ion, NO2-, the conjugate base of nitrous acid ? a) b) c) d) 25. 26. 2.0 x 10-11 5.1 x 10-4 2.0 x 10-3 2.2 x 10-2 The following equation represents the dissociation of acetic acid, CH3COOH, in water : CH3COOH (aq) + H2O (l) H3O+(aq) + CH3COO-(aq) Which one of the following is the expression for the Ka of acetic acid ? a) Ka = [H3O+][CH3COO-] b) Ka = [H3O+][CH3COO-] -----------------------[CH3COOH][H2O] c) Ka = [CH3COOH][H3O+] ------------------------[CH3COO-] d) Ka = [H3O+][CH3COO-] -----------------------[CH3COOH] Which of the following species is the weaker base in the equation H2O2 (aq) + H2O (l) HO2-(aq) + H3O+(aq) a) b) c) d) 27. 3.00 3.15 6.00 6.29 HO2-(aq) H2O (l) H2O2 (aq) H3O+(aq) Sn(OH)2 is insoluble in water but reacts with and is soluble in both dilute NaOH and dilute HCl. On the basis of this information, Sn(OH)2 could best be described as a) b) c) d) basic neutral acidic amphiprotic Acids and Bases Review 28. Which one of the following orders is correct for the Bronsted acids and bases in the equation C6H5NH2 (aq) + H2O  C6H5NH3+ (aq) + OH-(aq) a) b) c) d) 29. 5.88 x 10-9 1.70 x 10-6 5.88 x 105 1.70 x 108 What is the pH of a 2.0 M solution of benzoic acid (C6H5COOH) ? a) b) c) d) 34. pKw = 1/Kw pKw = (pH)(pOH) pKw = pH + pOH pKw = antilog Kw An aqueous solution of the base hydrazine, N2H4 , is in equilibrium with its conjugate acid, N2H5+. If the Kb for N2H4 is 1.70 x 10-6 at 20oC, what is the Ka for N2H5+ ? a) b) c) d) 33. The solution is pink. The solution is colourless. The [acid form] > [base form]. The [acid form] = [base form]. Which one of the following expressions is the correct expression for pKw ? a) b) c) d) 32. HCl HNO2 H3PO4 CH3COOH The indicator quinaldine red has a colourless acid form and a pink base form. Its Ka is 2.5 x 10-2. Which one of the following descriptions of an aqueous solution of quinaldine red at a pH of 7 is correct ? a) b) c) d) 31. acid + base  acid + base acid + base  base + acid base + acid  acid + base base + acid  base + acid Which of the following acids, at 1.0 M concentration, is LEAST ionized in solution ? a) b) c) d) 30. Page 1.94 2.24 3.88 4.48 Water at 25oC has a pH of 7 and the equation for the dissociation is : 2 H2O (l) + 57.3 kJ H3O+(aq) + OH-(aq). Water at 80oC could best be described as a) basic. b) acidic. c) neutral with a pH less than 7. d) neutral with a pH greater than 7. Acids and Bases Review 35. A Bronsted base is a substance which is a) b) c) d) 36. -9 10-9 9 109 Methyl orange, HMo, has a red acid form and a yellow base form. The yellow form would be represented by a) b) c) d) 41. H+ CO32H2CO3 HCO3- An indicator changes colour in the pH range 8.0 - 10.0. Its Ka value would be approximately a) b) c) d) 40. H3BO3 NH4+ H2SO3 HS- Which one of the following species is amphiprotic ? a) b) c) d) 39. H+ O2OH H2O Which one of the following species is the strongest acid ? a) b) c) d) 38. a proton donor. a proton acceptor. an electron donor an electron acceptor. Which of the following species is a conjugate base of OH- ? a) b) c) d) 37. Page H+ MoHMo H2Mo+ Consider the acid-base reaction : HSO4-(aq) + CH3COO-(aq) SO42-(aq) + CH3COOH (aq) In the above reaction, HSO4- acts as a) b) c) d) a base donating protons an acid donating protons a base accepting protons an acid accepting protons Acids and Bases Review 42. The equation for the dissolving of formic acid in water is HCOOH(aq) + H2O(l)  H3O+(aq) + HCOO-(aq) Which one of the following is the correct Ka expression for HCOOH ? a) [HCOOH] ------------------[H3O+][HCOO-] c) [HCOOH][H2O] --------------------[H3O+][HCOO-] 43. 45. d) [H3O+][HCOO-] ---------------------[HCOOH][H2O] 2.0 x 10-11 5.1 x 10-4 2.0 x 103 5.1 x 1010 Which is the stronger acid in the reaction : HNO2 (aq) + NH3 (aq) NH4+(aq) + NO2-(aq) a) NH3 (aq) b) NH4+(aq) c) NO2-(aq) d) HNO2 (aq45 What is the [H3O+] for a solution with a pH of 2.50 ? a) b) c) d) 46. b) [H3O+][HCOO-] ----------------------[HCOOH] The Ka value for nitrous acid is 5.1 x 10-4. Which of the following is the Kb value for the conjugate base of nitrous acid ? a) b) c) d) 44. Page 3.2 x 10-3 M 3.9 x 10-1 M 2.5 M 3.2 x 102 M A solution of strong acid has a pH of 3.00. What is the resulting pH if 1.0 L of the solution is diluted to 2.0 L with distilled water ? a) b) c) d) 1.50 2.70 3.30 6.00 Acids and Bases Review 47. Consider the following equation : HNO2 (aq) + HCOO-(aq)  NO2-(aq) + HCOOH(aq) Which of the following is an acid and conjugate base pair ? a) b) c) d) 48. Which of the following substances is amphiprotic ? a) b) c) d) 49. 1.0 M HCl 1.0 M HNO2 1.0 M CH3COOH 1.0 M H2CO3 Which of the following solutions would have the largest [H3O+] ? a) b) c) d) 53. the addition of a proton. the removal of a proton. the addition of an electron. the removal of an electron. Which of the following solutions is the best conductor ? a) b) c) d) 52. weak base. strong acid. proton donor. proton acceptor. To change a water molecule into a hydronium ion requires a) b) c) d) 51. CNHCl HCO3H2SO4 In the reaction NH3 (aq) + H2O(l)  NH4+(aq) + OH-(aq), the water molecule serves as a a) b) c) d) 50. HCOOH(aq) and HCOO-(aq) HNO2 (aq) and HCOO-(aq) NO2-(aq) and HCOO-(aq) HNO2 (aq) and HCOOH(aq) 1.0 M HA Ka = 1.0 x 10-6 1.0 M HB Ka = 1.0 x 10-3 1.0 M HC Ka = 1.0 x 10-8 1.0 M HD Ka = 1.0 x 10-12 As the strengths of the acids decrease, the strengths of their conjugate bases a) b) c) d) decrease. increase. stay the same. approach the strengths of the acids. Page Acids and Bases Review 54. What is the [H3O+] of a 2.0 M solution of the weak acid, HA HA(aq) + H2O(l)  H3O+(aq) + A-(aq) Ka = 1.8 x 10-7 a) b) c) d) 55. is a weak electrolyte. neutralizes a strong base. has a high molar concentration. is highly ionized in aqueous solutions. The anion HCO3- is acting as an acid in which of the following ? a) b) c) d) 59. 5 7 9 11 A strong acid differs from a weak acid in that a strong acid a) b) c) d) 58. yellow. purple. intermediate. colourless. A solution is tested with four acid-base indicators. The following colours resulted with each indicator : methyl red - yellow alizarin yellow - yellow phenol red - red thymolphthalein - colourless What is the pH of the solution ? a) b) c) d) 57. 9.0 x 10-8 M 7.2 x 10-5 M 4.2 x 10-4 M 6.0 x 10-4 M Bromocreosol purple is yellow in its acid form and purple in its base form. The colour change occurs in a pH range of 5 to 7. The colour of bromocreosol purple in 0.010 M KOH will be a) b) c) d) 56. Page HCO3-(aq) + OH-(aq)  H2CO3 (aq) + O2-(aq) HCO3-(aq) + H2O (l) H2CO3 (aq) + OH-(aq) HCO3-(aq) + H2O (l)  CO32-(aq) + H3O+(aq) HCO3-(aq) + H3O+(aq)  H2CO3 (aq) + H2O (l) Which term BEST describes the process represented by the following equation : F-(aq) + H2O (l)  OH-(aq) + HF (aq) a) b) c) d) Titration. Hydrolysis. Oxidation-reduction. Neutralization. Acids and Bases Review 60. A sample of peach juice has a pH of 3.50. What is the [H3O+] in this sample of juice ? a) b) c) d) 61. Page 2.9 x 10-15 M 3.2 x 10-4 M 5.4 x 10-1 M 3.2 x 103 M Which of the following solutions would have the lowest [H3O+] ? a) b) c) d) 1.0 M HF 1.0 M HCl 1.0 M HNO2 1.0 M CH3COOH a) b) c) d) 4.0 x 10-10 M 2.5 x 10-5 M 4.0 x 104 M 2.5 x 109 M 62. 63. Which of the following indicators will change colour at a pH of approximately 11? a) b) c) d) 64. Results of adding three indicators to separate samples of the same aqueous solution are as follows : orange IV - yellow methyl red - red methyl orange - yellow The best approximation for the pH of the above solution is a) b) c) d) 65. Phenolphthalein. Indigo carmine. Thymolphthalein. Alizarin yellow. 2.5 3.2 4.6 6.5 Cr(OH)3 is insoluble in water but will dissolve in both acidic and basic solutions. This indicates that it is a) b) c) d) amphiprotic. diprotic. isomeric. polymorphic. Acids and Bases Review 66. Which of the following is the conjugate acid of HS- ? a) b) c) d) 67. Page S2H2SH2S H3S+ An acid-base indicator is generally defined as a substance which a) changes colour when moles H+ = moles OHb) changes colour when the pH of the solution is 7. c) is used to detect whether the test solution contains an excess of positive or negative ions. d) changes colour within a definite pH range. 68 Which of the following indicators undergoes a colour change from red to yellow at [H3O+] = 3.2 x 10-4 M ? a) b) c) d) 69. Which test result will occur with a solution of 0.10 M HCl ? a) b) c) d) 70. HSO4HSO3H2SO3 H2SO4 H2O is added separately to each substance in the following pairs of solutions. With which pair does H2O display its amphiprotic nature? a) b) c) d) 72. A pH reading of 7.00. Reaction with Mg(s) to produce H2 (g) . Bromthymol blue indicator turns green. Precipitation reaction with 1.0 M Ba(NO3)2. Which of the following is the strongest acid ? a) b) c) d) 71. Thymol blue. Orange IV. Methyl orange. Alizarin yellow. HI and NH3 NaI and NH3 NaI and NaOH NaOH and NH3 If LiOH is added to water at 25oC then the a) b) c) d) [OH-] and the [H3O+] will both increase. [OH-] and the [H3O+] will both decrease. [OH-] will decrease while the [H3O+] will increase. [OH-] will increase while the [H3O+] will decrease. Acids and Bases Review 73. Page The Kb value for the dihydrogen citrate ion, H2C6H5O7- is a) b) c) d) 1.1 x 10-11 5.6 x 10-10 1.8 x 10-5 8.7 x 10-4 74. When neutral red is added to a sample of a solution, the colour of the solution is yellow-orange. When thymol blue is added to another sample of the same solution, the colour is yellow. What is the approximate [H3O+] in the solution ? a) b) c) d) 75. 6 x 10-12 M 1 x 10-8 M 1 x 10-6 M 2 x 10-3 M If the [OH-] = 5.2 x 10-3 M at 25oC, then the pH is a) b) c) d) 2.28 3.72 10.52 11.72 Part II: 76. Which one of the following equations represents a hydrolysis reaction ? a) b) c) d) 77. HI (g) + H2O (l)  I-(aq) + H3O+(aq) CuSO4 (s) + 5 H2O (l) CuSO4.5H2O (s) C6H5COOH (aq) + H2O (l)  C6H5COO-(aq) + H3O+(aq) NH4+(aq) + H2O (l)  NH3 (aq) + H3O+(aq) Which one of the following expressions best represent the equilibrium expression for the hydrolysis reaction of KNO2 ? a) [HNO2] ---------------[NO2-][H3O+] c) [HNO2][OH-] ----------------[NO2-][H2O] b) [HNO2][H2O] ----------------[NO2-][H3O+] d) [HNO2][OH-] ----------------[NO2-] Acids and Bases Review 78. Which one of the following gases will give the most acidic solution on dissolving in water ? a) b) c) d) 79. Ascorbic acid + H2O  Ascorbate- + H3O+ HCO3- + H2O  H3O+ + CO32HC2H3O2 + H2O  H3O+ + C2H3O2CO2 + H2O  H3O+ + HCO3- Which one of the following equations represents a titration reaction ? a) b) c) d) 82. NaBr and HBr NaCl and HCl NaF and HF NaI and HI If a person breathes too deeply and too rapidly, hyperventilation may occur, in which the pH of the blood becomes too high. A cure for this condition is to breathe several times into a paper bag held tightly over the mouth and nose. In this situation, which one of the following buffer reactions is responsible for bringing the pH of the blood back to its normal level of about 7.3 ? a) b) c) d) 81. CO2 (g) HBr (g) H2S (g) NH3 (g) If 0.100 M HNO3 is added dropwise to each of the solutions below (each containing two solutes and all at the same concentration), in which pair of solutions will the [H+] show the least change ? a) b) c) d) 80. Page NaOH (aq) + HCl (aq)  H2O (l) + NaCl (aq) CH3COOH (aq) + H2O (l)  H3O+(aq) + CH3COO-(aq) CH3COONa (aq) + H2O (l)  CH3COOH (aq) + NaOH (aq) NH4Cl (aq) + H2O (l)  NH3 (aq) + H3OCl (aq) If 50.0 mL of a 1.00 M NaOH solution are titrated with 51.0 mL of a 1.00 M HCl solution, then what is the pH of the resulting solution ? a) b) c) d) 2.00 3.00 9.90 12.0 Acids and Bases Review 83. Which one of the following equations contains the conjugate acid-base pair from which a buffer solution can be prepared ? a) b) c) d) 84. 6.00 7.00 8.00 9.00 During the titration of 50.0 mL of a 0.200 M KOH solution with 0.200 M HNO3, 20.0 mL of the HNO3 is added. What is the pH at this point in the titration ? a) b) c) d) 88. NH4Cl, K2SO4, Na2CO3 K2SO4, NH4Cl, Na2CO3 Na2CO3, K2SO4, NH4Cl NH4Cl, Na2CO3, K2SO4 What is the pH of the solution which results when 100.0 mL of a 0.050 M solution of NaOH is titrated with 200.0 mL of a 0.025 M solution of HCl ? a) b) c) d) 87. NaI NaNO2 Na3PO4 Na2SO4 Which one of the following sets shows the correct order of increasing pH of the aqueous solutions of the three salts if equal concentrations are used ? a) b) c) d) 86. HCl + H2O  H3O+ + ClHClO4 + H2O  H3O+ + ClO4H2SO4 + H2O H3O+ + HSO4HNO2 + H2O  H3O+ + NO2- Which one of the following salts will show the greatest amount of hydrolysis in water if equal concentrations are used ? a) b) c) d) 85. Page 0.92 1.07 12.93 13.08 In which of the following buffer solutions will the addition of H3O+ cause the equilibrium to shift to the left ? (1) HF + H2O  H3O+ + F(2) H2PO4- + H3O+  H3PO4 + H2O (3) HPO42- + OH-  PO43- + H2O (4) HSO3- + OH-  SO32- + H2O a) 1 only b) 2 only c) 3 and 4 only d) 1, 3, and 4 Acids and Bases Review 89. Which one of the following equations contains the conjugate acid-base pair form which a buffer solution can be prepared ? a) b) c) d) 90. undissociated Na2S. more HS-(aq) than S2-(aq). more H3O+(aq) than OH-(aq). strongly hydrolyzed Na+(aq). When selecting an indicator for any titration, how should the indicator endpoint compare to the titration stoichiometric point ? a) b) c) d) 94. 2.30 2.60 11.40 11.70 A dilute solution of Na2S will contain a) b) c) d) 93. CH3COOH(aq) + H2O(l)  H3O+(aq) + CH3COO-(aq) 2 HBr(aq) + Cl2 (aq)  2 HCl(aq) + Br2(aq) KHCO3(aq) + HBr(aq)  KBr(aq) + H2O(l) + CO2 (g) 3Zn(s) + 2NO3-(aq) + 8H+(aq)  3Zn2+(aq) + 2NO2(g) + 4H2O(l) What is the pH of a 0.0025 M solution of lime water, Ca(OH)2 ? a) b) c) d) 921. HI(aq) + H2O(l)  H3O+(aq) + I-(aq) HBr(aq) + H2O(l)  H3O+(aq) + Br-(aq) H2SO4(aq) + H2O(l)  H3O+(aq) + HSO4-(aq) H2CO3(aq) + H2O(l)  H3O+(aq) + HCO3-(aq) Which one of the following equations could represent a titration reaction ? a) b) c) d) 91. Page The endpoint and the stoichiometric point should coincide. The endpoint should be before the stoichiometric point. The endpoint should be after the stoichiometric point. The endpoint and stoichiometric point should both be at pH 9. Which one of the following describes the pH at the stoichiometric point in the titration of a strong acid with a strong base ? a) b) c) d) pH = 0 pH = 7 0 < pH < 7 7 < pH < 14 Acids and Bases Review 95. In a titration, 20.0 mL of 0.50 M NaOH solution reacts completely with 30.0 mL of H2SO4 solution. What is the initial concentration of the H2SO4 solution ? a) b) c) d) 96. 1.18 7.00 12.82 13.30 A Ba(OH)2 solution is titrated with a solution of HNO3 to the stoichiometric point. Which of the following conditions exists at the stoichiometric point ? a) b) c) d) 101. A solution of known volume. A solution of known concentration. A solution prepared at STP conditions. A solution prepared at 25oC and standard pressure. 25 mL of 0.20 M HCl solution are added to 50.0 mL of 0.20 M KOH solution. What is the pH of the resulting solution ? a) b) c) d) 100. KClO4 Fe(NO3)3 NaCH3COO AlBr3 Which of the following is the best definition for a standard solution ? a) b) c) d) 99. 0.00 1.0 7.0 13.0 Which of the following salts will produce a basic solution when it dissolves in water ? a) b) c) d) 98. 0.17 M 0.33 M 0.40 M 0.67 M 30.0 mL of 0.50 M HCl solution are titrated with 20.0 mL of 0.50 M NaOH solution. What is the pH of the resulting solution ? a) b) c) d) 97. Page The mixture is highly acidic. The mixture is highly basic. Moles of Ba(OH)2 originally present equals moles of HNO3 added. Moles of H+ from the acid equals moles of OH- from the base. A buffer solution could be prepared by mixing a 1.0 M solution of Na2CO3 with an equal volume of a 1.0 M solution of a) NaCl b) NaOH c) NaHCO3 d) Na2SO4 Acids and Bases Review 102. Which of the following 1.0 M solutions is basic ? a) b) c) d) 103. 105. a) 0.17 M b) 0.33 M c) 0.40 M d) 0.67 M What is the pOH of a 0.15 M solution of RbOH ? HCl and NaCl CH3COOH and NaCl NaCl and NaCH3COO CH3COOH and NaCH3COO Which of the following 0.10 M solutions will have the highest [OH-] ? a) b) c) d) 108. -0.82 0.41 0.82 13.18 Which of the following pairs of chemicals could be used to prepare a buffer solution ? a) b) c) d) 107. the volume of the base equals twice the volume of the acid. the mass of the acid equals the mass of the base. the number of moles of acid equals the number of moles of base. the volume of acid equals the volume of base. In a titration, 20.0 mL of 0.50 M NaOH solution reacts completely with 30.0 mL of H2SO4 solution. What is the initial concentration of the H2SO4 solution ? a) b) c) d) 106. KCl NH4NO3 NaClO4 Na2CO3 A titration of 0.1 M HCl with 0.2 M NaOH will reach an equivalance point when a) b) c) d) 104. Page NaCl K3PO4 Cr(NO3)3 CH3COOH Each of the following 1.00 M acids is titrated with 1.00 M NaOH. Which sample requires the greatest volume of NaOH for complete reaction ? a) b) c) d) 45.0 mL of oxalic acid, H2C2O4 50.0 mL of sulphuric acid, H2SO4 75.0 mL of hydrochloric acid, HCl 90.0 mL of acetic acid, CH3COOH Acids and Bases Review 109 When 20.0 mL of 0.200 M HCl is added to 40.0 mL of 0.100 M NaOH, the [H3O+] in the resulting solution is a) b) c) d) 110. ZnO MgO ClO2 Na2O Which of the following indicators is most suitable for the titration of 0.10 M NH3 with 0.10 M HCl ? a) b) c) d) 115. NaOH is a stronger base than C6H5COOH. C6H5COOH is a stronger acid than NaOH. The [NaOH] is greater than the [C6H5COOH]. The salt solution formed undergoes hydrolysis to form OH- ions. Which compound forms an acid when dissolved in water ? a) b) c) d) 114. a base since its Kb < its Ka a base since its Kb > its Ka an acid since its Kb < its Ka an acid since its Kb > its Ka Which of the following best explains why the equivalence point is above pH 7 for the neutralization of 0.2 M C6H5COOH with 0.3 M NaOH ? a) b) c) d) 113. 6.25 mL 12.5 mL 25.0 mL 50.0 mL HPO42- in water will act as a) b) c) d) 112. 0.100 M 0.0333 M 1.00 x 10-7 M 0.00 M What volume of 0.0200 M Ca(OH)2 solution is required to neutralize 25.0 mL of 0.0100 M HCl ? a) b) c) d) 111. Page Indigo carmine Alizarin yellow Phenolphthalein Bromcresol green A water solution of the salt RbNO2 will be a) b) c) d) basic acidic neutral amphiprotic Acids and Bases Review 116. In the net ionic equation showing the complete neutralization of Mg(OH)2 by HCl, one of the products is a) b) c) d) 117. exactly equal to 2.0 M slightly less than 1.0 M slightly larger than 2.0 M slightly larger than 1.0 M Which of the following compounds will form a basic solution when dissloved in water ? a) b) c) d) 119. H2O (l) H3O+(aq) MgCl2 (s) OH-(aq) Which of the following best describes the [CH3COO-] of a buffer solution containing 1.0 M NaCH3COO(aq) and 1.0 M CH3COOH(aq) ? a) b) c) d) 118. Page BaO SO2 ClO2 P2O5 The pH of a 0.10 M solution of NaHSO3 is approximately a) 1 b) 4 c) 7 d) 10 Acids and Bases Review Page WRITTEN RESPONSE QUESTIONS Your steps and assumptions leading to a solution must be written. In questions involving calculation, full marks will not be given for providing only an answer. Students will be expected to communicate the knowledge and understanding of chemical principles in a clear and logical manner. Part 1: 1. Calculate Kb for H2BO3-, the conjugate base for boric acid, H3BO3. (2 marks) 2. A 0.10 M solution of a weak acid HX has a pH of 4.26. Calculate the value of Ka for HX. (3 marks) 3. Write the equilibrium equation for the reaction of the HS- ion with water to produce a basic solution. State whether the reactants or products are favoured. (2 marks) 4. A 0.60 M solution of the weak acid HX is found to have a pH = 4.30. Determine Ka for this acid. (3 marks) 5. Calculate the [H3O+] of a solution with a pOH of 3.86. (2 marks) 6. Determine the [H+] in 2.4 M HF. (2 marks) 7. If you were given two unknown acids of equal concentration, briefly describe how you would identify the stronger acid. What testing material or instrument would you use, and how would you interpret your results ? (2 marks) 8. a) Compare the ease with which the first hydrogen ion (proton) is removed from a diprotic acid in relation to the ease of removal of the second hydrogen ion. (1 mark) b) Use an example from the table of acids to illustrate the above situation. (1 mark) 9. The weak acid, HClO, has a Ka of 3.24 x 10-8. Calculate the pH of a 0.076 M solution of HClO. (3 marks) 10. A solution with a pH of 4.20 is found to contain twice as much conjugate base as acid. Calculate the value of the acid dissociation constant (Ka) for this monoprotic acid. (3 marks) 11. Identify each substance in the following equation as either an acid or a base, and then state whether the position of equilibrium favours the reactants or products. (3 marks) HOOCCOO- (aq) + H2PO4-(aq)  HOOCCOOH (aq) + HPO42- (aq) Acids and Bases Review 12. Page Calculate the pH of a 0.40 M solution of benzoic acid, C6H5COOH. Ka for C6H5COOH is 6.6 x 10-5. (3 marks) Part 2: 13. a) Write the equation for the acid-base equilibrium reaction that occurs when aqueous solutions containing equal concentrationsof HCO3- and SO32- are mixed. (2 marks) b) What acid in the above equilibrium will be present in the greatest concentration ? (1 mark) 14. Write the net ionic equation for the following reaction: potassium hydroxide neutralized by acetic acid. (2 marks) 15. Calculate the pH of a solution made by dissolving 3.75 g of RbOH in 79.8 mL of 0.18 M HNO3. Assume no volume change. (5 marks) 16. The Ka and Kb values for the HPO42- ion in water are given below : HPO42-(aq) Ka = 4.4 x 10-13 HPO42-(aq) Kb = 1.6 x 10-7 Indicate whether an aqueous solution of Na2HPO4 is basic or acidic, and explain your answer with reference to the Ka and Kb values given above. (2 marks) 17. Calculate the mass of NaOH(s) that would have to be added to10.0 mL of a 2.00 M HNO3 solution to obtain a pH of 1.00. (4 marks) 18. What is the function of a buffer in a chemical system ? (1 mark) 19. Combustion of coal which contains sulphur produces a gaseous sulphur compound. This compound, when released into the atmosphere, undergoes a series of reactions eventually forming "acid rain". Explain this process, and support your answer with appropriate equations. (3 marks) 20. In an acid-base titration, it was found that 18.4 mL of 0.200 M NaOH was required to neutralize a 0.22 g sample of a monoprotic acid. What is the mass of one mole of this acid ? (3 marks) 21. 25.0 mL of 0.025 M Ca(OH)2 is completely neutralized by 28.3 mL of HCl solution. What is the concentration of the HCl solution ? (3 marks) Ca(OH)2 + 2 HCl CaCl2 + 2 H2O 22. Write a balanced equation showing the formation of a basic aqueous solution using the metal oxide SrO. (1 mark) 23. SO2 is a waste product in some industrial processes. State the environmental problem associated with SO2 (g), write the equation that accounts for this problem, and give one effect on the natural environment. (2 marks)