Chapter 19 Ionic Equilibria in Aqueous Systems Chapter 19 Ionic Equilibria in Aqueous Systems 1 Which of the following aqueous mixtures would be a buffer system A HCl NaCl D H2SO4 CH3COOH B HNO3 NaNO3 E NH3 NaOH C H3PO4 H2PO4Ans C 2 Which if any of the following aqueous mixtures would be a buffer system A CH3COOH NaH2PO4 B H2CO3 HCO3C H2PO4 HCO3D HSO4 HSO3E None of these will be a buffer solution Ans B 3 Equal volumes of the following pairs of solutions are mixed Which pair will produce a buffer solution A 0 10 mol L 1 HCl and 0 05 mol L 1 NaOH B 0 10 mol L 1 HCl and 0 15 mol L 1 NH3 C 0 10 mol L 1 HCl and 0 05 mol L 1 NH3 D 0 10 mol L 1 HCl and 0 20 mol L 1 CH3COOH E 0 10 mol L 1 HCl and 0 20 mol L 1 NaCl Ans B 4 Which one of the following aqueous solutions when mixed with an equal volume of 0 10 mol L 1 aqueous NH3 will produce a buffer solution A 0 10 mol L 1 HCl D 0 050 mol L 1 NaOH 1 B 0 20 mol L HCl E 0 20 mol L 1 NH4Cl C 0 10 mol L 1 CH3COOH Ans E 5 Which one of the following pairs of 0 100 mol L 1 solutions when mixed will produce a buffer solution A 50 mL of aqueous CH3COOH and 25 mL of aqueous HCl B 50 mL of aqueous CH3COOH and 100 mL of aqueous NaOH C 50 mL of aqueous NaOH and 25 mL of aqueous HCl D 50 mL of aqueous CH3COONa and 25 mL of aqueous NaOH E 50 mL of aqueous CH3COOH and 25 mL of aqueous CH3COONa Ans E Page 255 2013 by McGraw Hill Education This is proprietary material solely for authorized instructor use Not authorized for sale or distribution in any manner This document may not be copied scanned duplicated forwarded distributed or posted on a website in whole or part Chapter 19 Ionic Equilibria in Aqueous Systems 6 Which of the following has the highest buffer capacity A 0 10 M H2PO4 0 10 M HPO42B 0 50 M H2PO4 0 10 M HPO42C 0 10 M H2PO4 0 50 M HPO42D 0 50 M H2PO4 0 50 M HPO42E They all have the same buffer capacity Ans D 7 Which of the following acids should be used to prepare a buffer with a pH of 4 5 A HOC6H4OCOOH Ka 1 0 10 3 D C5H5O5COOH 2 Ka 4 0 10 6 B C6H4 COOH 2 Ka 2 9 10 4 E HBrO Ka 2 3 10 9 5 C CH3COOH Ka 1 8 10 Ans C 8 Citric acid has an acid dissociation constant of 8 4 10 4 It would be most effective for preparation of a buffer with a pH of A 2 B 3 C 4 D 5 E 6 Ans B 9 A buffer is to be prepared by adding solid sodium acetate to 0 10 M CH3COOH Which of the following concentrations of sodium acetate will produce the most effective buffer A 3 0 M CH3COONa D 1 5 M CH3COONa B 2 5 M CH3COONa E 0 30 M CH3COONa C 2 0 M CH3COONa Ans E 10 An acetate buffer has a pH of 4 40 Which of the following changes will cause the pH to decrease A dissolving a small amount of solid sodium acetate B adding a small amount of dilute hydrochloric acid C adding a small amount of dilute sodium hydroxide D dissolving a small amount of solid sodium chloride E diluting the buffer solution with water Ans B 11 A phosphate buffer H2PO4 HPO42 has a pH of 8 3 Which of the following changes will cause the pH to increase A dissolving a small amount of Na2HPO4 B dissolving a small amount of NaH2PO4 C adding a small amount of dilute hydrochloric acid D adding a small amount of dilute phosphoric acid E making the buffer more concentrated by removing some water Ans A Page 256 2013 by McGraw Hill Education This is proprietary material solely for authorized instructor use Not authorized for sale or distribution in any manner This document may not be copied scanned duplicated forwarded distributed or posted on a website in whole or part Chapter 19 Ionic Equilibria in Aqueous Systems 12 What will be the effect of adding 0 5 mL of 0 1 M NaOH to 100 mL of an acetate buffer in which CH3COOH CH3COO 0 5 M A The pH will increase slightly B The pH will increase significantly C The pH will decrease slightly D The pH will decrease significantly E Since it is a buffer solution the pH will not be affected Ans A 13 What will be the effect of adding 0 5 mL of 0 1 M HCl to 100 mL of a phosphate buffer in which H2PO4 HPO42 0 35 M A The pH will increase slightly B The pH will increase significantly C The pH will decrease slightly D The pH will decrease significantly E Since it is a buffer solution the pH will not be affected Ans C 14 Buffer solutions with the component concentrations shown below were prepared Which of them should have the lowest pH A CH3COOH 0 25 M CH3COO 0 25 M B CH3COOH 0 75 M CH3COO 0 75 M C CH3COOH 0 75 M CH3COO 0 25 M D CH3COOH 0 25 M CH3COO 0 75 M E CH3COOH 1 00 M CH3COO 1 00 M Ans C 15 Buffer solutions with the component concentrations shown below were prepared Which of them should have the highest pH A H2PO4 0 50 M HPO42 0 50 M B H2PO4 1 0 M HPO42 1 0 M C H2PO4 1 0 M HPO42 0 50 M D H2PO4 0 50 M HPO42 1 0 M E H2PO4 0 75 M HPO42 1 0 M Ans D 16 A buffer is prepared by adding 0 5 mol of solid sodium hydroxide to 1 0 L of 1 0 M acetic acid CH3COOH What is the pH of the buffer A The pH will be pKa 0 30 where pKa is that of acetic acid B The pH will be greater than the pKa for acetic acid C The pH will be less than the value in answer a D The pH will be equal to the pKa for acetic acid E More information is needed to solve the problem Ans D Page 257 2013 by McGraw Hill Education This is proprietary material solely for authorized instructor use Not authorized for sale or distribution in any manner This document may not be copied scanned duplicated forwarded distributed or posted on a website in whole or part Chapter 19 Ionic Equilibria in Aqueous Systems 17 A solution is prepared by adding 100 mL of 0 2 M hydrochloric acid to 100 mL of 0 4 M sodium formate Is this a buffer solution …